diff --git a/gpx/api/gpx.api b/gpx/api/gpx.api
index 13e27134..d4891e80 100644
--- a/gpx/api/gpx.api
+++ b/gpx/api/gpx.api
@@ -99,8 +99,8 @@ public final class org/maplibre/spatialk/gpx/Copyright$Companion {
 public final class org/maplibre/spatialk/gpx/Document {
 	public static final field Companion Lorg/maplibre/spatialk/gpx/Document$Companion;
 	public fun <init> ()V
-	public fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;)V
-	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Ljava/lang/String;
 	public final fun component2 ()Ljava/lang/String;
 	public final fun component3 ()Ljava/lang/String;
@@ -108,10 +108,12 @@ public final class org/maplibre/spatialk/gpx/Document {
 	public final fun component5 ()Ljava/util/List;
 	public final fun component6 ()Ljava/util/List;
 	public final fun component7 ()Ljava/util/List;
-	public final fun copy (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;)Lorg/maplibre/spatialk/gpx/Document;
-	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Document;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Document;
+	public final fun component8 ()Lnl/adaptivity/xmlutil/dom2/Element;
+	public final fun copy (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)Lorg/maplibre/spatialk/gpx/Document;
+	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Document;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Metadata;Ljava/util/List;Ljava/util/List;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Document;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getCreator ()Ljava/lang/String;
+	public final fun getExtensions ()Lnl/adaptivity/xmlutil/dom2/Element;
 	public final fun getMetadata ()Lorg/maplibre/spatialk/gpx/Metadata;
 	public final fun getRoutes ()Ljava/util/List;
 	public final fun getSchemaLocation ()Ljava/lang/String;
@@ -212,8 +214,8 @@ public final class org/maplibre/spatialk/gpx/Link$Companion {
 public final class org/maplibre/spatialk/gpx/Metadata {
 	public static final field Companion Lorg/maplibre/spatialk/gpx/Metadata$Companion;
 	public fun <init> ()V
-	public fun <init> (Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;)V
-	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;Lnl/adaptivity/xmlutil/dom2/Element;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;Lnl/adaptivity/xmlutil/dom2/Element;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Ljava/lang/String;
 	public final fun component2 ()Ljava/lang/String;
 	public final fun component3 ()Lorg/maplibre/spatialk/gpx/Author;
@@ -222,13 +224,15 @@ public final class org/maplibre/spatialk/gpx/Metadata {
 	public final fun component6 ()Lkotlin/time/Instant;
 	public final fun component7 ()Ljava/lang/String;
 	public final fun component8 ()Lorg/maplibre/spatialk/gpx/Bounds;
-	public final fun copy (Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;)Lorg/maplibre/spatialk/gpx/Metadata;
-	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Metadata;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Metadata;
+	public final fun component9 ()Lnl/adaptivity/xmlutil/dom2/Element;
+	public final fun copy (Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;Lnl/adaptivity/xmlutil/dom2/Element;)Lorg/maplibre/spatialk/gpx/Metadata;
+	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Metadata;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Author;Lorg/maplibre/spatialk/gpx/Copyright;Ljava/util/List;Lkotlin/time/Instant;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Bounds;Lnl/adaptivity/xmlutil/dom2/Element;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Metadata;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getAuthor ()Lorg/maplibre/spatialk/gpx/Author;
 	public final fun getBounds ()Lorg/maplibre/spatialk/gpx/Bounds;
 	public final fun getCopyright ()Lorg/maplibre/spatialk/gpx/Copyright;
 	public final fun getDescription ()Ljava/lang/String;
+	public final fun getExtensions ()Lnl/adaptivity/xmlutil/dom2/Element;
 	public final fun getKeywords ()Ljava/lang/String;
 	public final fun getLink ()Ljava/util/List;
 	public final fun getName ()Ljava/lang/String;
@@ -254,7 +258,8 @@ public final class org/maplibre/spatialk/gpx/Metadata$Companion {
 
 public final class org/maplibre/spatialk/gpx/Route {
 	public static final field Companion Lorg/maplibre/spatialk/gpx/Route$Companion;
-	public fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;)V
+	public fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Ljava/lang/String;
 	public final fun component2 ()Ljava/lang/String;
 	public final fun component3 ()Ljava/lang/String;
@@ -263,11 +268,13 @@ public final class org/maplibre/spatialk/gpx/Route {
 	public final fun component6 ()Ljava/lang/Integer;
 	public final fun component7 ()Ljava/lang/String;
 	public final fun component8 ()Ljava/util/List;
-	public final fun copy (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;)Lorg/maplibre/spatialk/gpx/Route;
-	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Route;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Route;
+	public final fun component9 ()Lnl/adaptivity/xmlutil/dom2/Element;
+	public final fun copy (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)Lorg/maplibre/spatialk/gpx/Route;
+	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Route;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Route;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getComment ()Ljava/lang/String;
 	public final fun getDescription ()Ljava/lang/String;
+	public final fun getExtensions ()Lnl/adaptivity/xmlutil/dom2/Element;
 	public final fun getLink ()Ljava/lang/String;
 	public final fun getName ()Ljava/lang/String;
 	public final fun getNumber ()Ljava/lang/Integer;
@@ -300,8 +307,8 @@ public final class org/maplibre/spatialk/gpx/RouteKt {
 public final class org/maplibre/spatialk/gpx/Track {
 	public static final field Companion Lorg/maplibre/spatialk/gpx/Track$Companion;
 	public fun <init> ()V
-	public fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;)V
-	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Ljava/lang/String;
 	public final fun component2 ()Ljava/lang/String;
 	public final fun component3 ()Ljava/lang/String;
@@ -310,11 +317,13 @@ public final class org/maplibre/spatialk/gpx/Track {
 	public final fun component6 ()Ljava/lang/Integer;
 	public final fun component7 ()Ljava/lang/String;
 	public final fun component8 ()Ljava/util/List;
-	public final fun copy (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;)Lorg/maplibre/spatialk/gpx/Track;
-	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Track;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Track;
+	public final fun component9 ()Lnl/adaptivity/xmlutil/dom2/Element;
+	public final fun copy (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)Lorg/maplibre/spatialk/gpx/Track;
+	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Track;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/Integer;Ljava/lang/String;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Track;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getComment ()Ljava/lang/String;
 	public final fun getDescription ()Ljava/lang/String;
+	public final fun getExtensions ()Lnl/adaptivity/xmlutil/dom2/Element;
 	public final fun getLink ()Lorg/maplibre/spatialk/gpx/Link;
 	public final fun getName ()Ljava/lang/String;
 	public final fun getNumber ()Ljava/lang/Integer;
@@ -347,11 +356,14 @@ public final class org/maplibre/spatialk/gpx/TrackKt {
 
 public final class org/maplibre/spatialk/gpx/TrackSegment {
 	public static final field Companion Lorg/maplibre/spatialk/gpx/TrackSegment$Companion;
-	public fun <init> (Ljava/util/List;)V
+	public fun <init> (Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)V
+	public synthetic fun <init> (Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()Ljava/util/List;
-	public final fun copy (Ljava/util/List;)Lorg/maplibre/spatialk/gpx/TrackSegment;
-	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/TrackSegment;Ljava/util/List;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/TrackSegment;
+	public final fun component2 ()Lnl/adaptivity/xmlutil/dom2/Element;
+	public final fun copy (Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;)Lorg/maplibre/spatialk/gpx/TrackSegment;
+	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/TrackSegment;Ljava/util/List;Lnl/adaptivity/xmlutil/dom2/Element;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/TrackSegment;
 	public fun equals (Ljava/lang/Object;)Z
+	public final fun getExtensions ()Lnl/adaptivity/xmlutil/dom2/Element;
 	public final fun getPoints ()Ljava/util/List;
 	public fun hashCode ()I
 	public fun toString ()Ljava/lang/String;
@@ -374,8 +386,8 @@ public final class org/maplibre/spatialk/gpx/TrackSegment$Companion {
 
 public final class org/maplibre/spatialk/gpx/Waypoint {
 	public static final field Companion Lorg/maplibre/spatialk/gpx/Waypoint$Companion;
-	public fun <init> (DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;)V
-	public synthetic fun <init> (DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Lnl/adaptivity/xmlutil/dom2/Element;)V
+	public synthetic fun <init> (DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Lnl/adaptivity/xmlutil/dom2/Element;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun component1 ()D
 	public final fun component10 ()Ljava/lang/String;
 	public final fun component11 ()Lorg/maplibre/spatialk/gpx/Link;
@@ -389,6 +401,7 @@ public final class org/maplibre/spatialk/gpx/Waypoint {
 	public final fun component19 ()Ljava/lang/Double;
 	public final fun component2 ()D
 	public final fun component20 ()Ljava/lang/Double;
+	public final fun component21 ()Lnl/adaptivity/xmlutil/dom2/Element;
 	public final fun component3 ()Ljava/lang/Double;
 	public final fun component4 ()Lkotlin/time/Instant;
 	public final fun component5 ()Ljava/lang/Double;
@@ -396,14 +409,15 @@ public final class org/maplibre/spatialk/gpx/Waypoint {
 	public final fun component7 ()Ljava/lang/String;
 	public final fun component8 ()Ljava/lang/String;
 	public final fun component9 ()Ljava/lang/String;
-	public final fun copy (DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;)Lorg/maplibre/spatialk/gpx/Waypoint;
-	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Waypoint;DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Waypoint;
+	public final fun copy (DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Lnl/adaptivity/xmlutil/dom2/Element;)Lorg/maplibre/spatialk/gpx/Waypoint;
+	public static synthetic fun copy$default (Lorg/maplibre/spatialk/gpx/Waypoint;DDLjava/lang/Double;Lkotlin/time/Instant;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Lorg/maplibre/spatialk/gpx/Link;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/Integer;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Ljava/lang/Double;Lnl/adaptivity/xmlutil/dom2/Element;ILjava/lang/Object;)Lorg/maplibre/spatialk/gpx/Waypoint;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getComment ()Ljava/lang/String;
 	public final fun getDescription ()Ljava/lang/String;
 	public final fun getDgpsAge ()Ljava/lang/Double;
 	public final fun getDgpsId ()Ljava/lang/Double;
 	public final fun getElevation ()Ljava/lang/Double;
+	public final fun getExtensions ()Lnl/adaptivity/xmlutil/dom2/Element;
 	public final fun getFix ()Ljava/lang/String;
 	public final fun getGeoIdHeight ()Ljava/lang/Double;
 	public final fun getHorizontalDop ()Ljava/lang/Double;
diff --git a/gpx/api/gpx.klib.api b/gpx/api/gpx.klib.api
index 41accd09..f58b33cf 100644
--- a/gpx/api/gpx.klib.api
+++ b/gpx/api/gpx.klib.api
@@ -106,10 +106,12 @@ final class org.maplibre.spatialk.gpx/Copyright { // org.maplibre.spatialk.gpx/C
 }
 
 final class org.maplibre.spatialk.gpx/Document { // org.maplibre.spatialk.gpx/Document|null[0]
-    constructor <init>(kotlin/String = ..., kotlin/String = ..., kotlin/String = ..., org.maplibre.spatialk.gpx/Metadata? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Track> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Route> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ...) // org.maplibre.spatialk.gpx/Document.<init>|<init>(kotlin.String;kotlin.String;kotlin.String;org.maplibre.spatialk.gpx.Metadata?;kotlin.collections.List<org.maplibre.spatialk.gpx.Track>;kotlin.collections.List<org.maplibre.spatialk.gpx.Route>;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>){}[0]
+    constructor <init>(kotlin/String = ..., kotlin/String = ..., kotlin/String = ..., org.maplibre.spatialk.gpx/Metadata? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Track> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Route> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ..., nl.adaptivity.xmlutil.dom2/Element? = ...) // org.maplibre.spatialk.gpx/Document.<init>|<init>(kotlin.String;kotlin.String;kotlin.String;org.maplibre.spatialk.gpx.Metadata?;kotlin.collections.List<org.maplibre.spatialk.gpx.Track>;kotlin.collections.List<org.maplibre.spatialk.gpx.Route>;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
 
     final val creator // org.maplibre.spatialk.gpx/Document.creator|{}creator[0]
         final fun <get-creator>(): kotlin/String // org.maplibre.spatialk.gpx/Document.creator.<get-creator>|<get-creator>(){}[0]
+    final val extensions // org.maplibre.spatialk.gpx/Document.extensions|{}extensions[0]
+        final fun <get-extensions>(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Document.extensions.<get-extensions>|<get-extensions>(){}[0]
     final val metadata // org.maplibre.spatialk.gpx/Document.metadata|{}metadata[0]
         final fun <get-metadata>(): org.maplibre.spatialk.gpx/Metadata? // org.maplibre.spatialk.gpx/Document.metadata.<get-metadata>|<get-metadata>(){}[0]
     final val routes // org.maplibre.spatialk.gpx/Document.routes|{}routes[0]
@@ -130,7 +132,8 @@ final class org.maplibre.spatialk.gpx/Document { // org.maplibre.spatialk.gpx/Do
     final fun component5(): kotlin.collections/List<org.maplibre.spatialk.gpx/Track> // org.maplibre.spatialk.gpx/Document.component5|component5(){}[0]
     final fun component6(): kotlin.collections/List<org.maplibre.spatialk.gpx/Route> // org.maplibre.spatialk.gpx/Document.component6|component6(){}[0]
     final fun component7(): kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> // org.maplibre.spatialk.gpx/Document.component7|component7(){}[0]
-    final fun copy(kotlin/String = ..., kotlin/String = ..., kotlin/String = ..., org.maplibre.spatialk.gpx/Metadata? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Track> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Route> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ...): org.maplibre.spatialk.gpx/Document // org.maplibre.spatialk.gpx/Document.copy|copy(kotlin.String;kotlin.String;kotlin.String;org.maplibre.spatialk.gpx.Metadata?;kotlin.collections.List<org.maplibre.spatialk.gpx.Track>;kotlin.collections.List<org.maplibre.spatialk.gpx.Route>;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>){}[0]
+    final fun component8(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Document.component8|component8(){}[0]
+    final fun copy(kotlin/String = ..., kotlin/String = ..., kotlin/String = ..., org.maplibre.spatialk.gpx/Metadata? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Track> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Route> = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ..., nl.adaptivity.xmlutil.dom2/Element? = ...): org.maplibre.spatialk.gpx/Document // org.maplibre.spatialk.gpx/Document.copy|copy(kotlin.String;kotlin.String;kotlin.String;org.maplibre.spatialk.gpx.Metadata?;kotlin.collections.List<org.maplibre.spatialk.gpx.Track>;kotlin.collections.List<org.maplibre.spatialk.gpx.Route>;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
     final fun equals(kotlin/Any?): kotlin/Boolean // org.maplibre.spatialk.gpx/Document.equals|equals(kotlin.Any?){}[0]
     final fun hashCode(): kotlin/Int // org.maplibre.spatialk.gpx/Document.hashCode|hashCode(){}[0]
     final fun toString(): kotlin/String // org.maplibre.spatialk.gpx/Document.toString|toString(){}[0]
@@ -213,7 +216,7 @@ final class org.maplibre.spatialk.gpx/Link { // org.maplibre.spatialk.gpx/Link|n
 }
 
 final class org.maplibre.spatialk.gpx/Metadata { // org.maplibre.spatialk.gpx/Metadata|null[0]
-    constructor <init>(kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Author? = ..., org.maplibre.spatialk.gpx/Copyright? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Link> = ..., kotlin.time/Instant? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Bounds? = ...) // org.maplibre.spatialk.gpx/Metadata.<init>|<init>(kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Author?;org.maplibre.spatialk.gpx.Copyright?;kotlin.collections.List<org.maplibre.spatialk.gpx.Link>;kotlin.time.Instant?;kotlin.String?;org.maplibre.spatialk.gpx.Bounds?){}[0]
+    constructor <init>(kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Author? = ..., org.maplibre.spatialk.gpx/Copyright? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Link> = ..., kotlin.time/Instant? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Bounds? = ..., nl.adaptivity.xmlutil.dom2/Element? = ...) // org.maplibre.spatialk.gpx/Metadata.<init>|<init>(kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Author?;org.maplibre.spatialk.gpx.Copyright?;kotlin.collections.List<org.maplibre.spatialk.gpx.Link>;kotlin.time.Instant?;kotlin.String?;org.maplibre.spatialk.gpx.Bounds?;nl.adaptivity.xmlutil.dom2.Element?){}[0]
 
     final val author // org.maplibre.spatialk.gpx/Metadata.author|{}author[0]
         final fun <get-author>(): org.maplibre.spatialk.gpx/Author? // org.maplibre.spatialk.gpx/Metadata.author.<get-author>|<get-author>(){}[0]
@@ -223,6 +226,8 @@ final class org.maplibre.spatialk.gpx/Metadata { // org.maplibre.spatialk.gpx/Me
         final fun <get-copyright>(): org.maplibre.spatialk.gpx/Copyright? // org.maplibre.spatialk.gpx/Metadata.copyright.<get-copyright>|<get-copyright>(){}[0]
     final val description // org.maplibre.spatialk.gpx/Metadata.description|{}description[0]
         final fun <get-description>(): kotlin/String? // org.maplibre.spatialk.gpx/Metadata.description.<get-description>|<get-description>(){}[0]
+    final val extensions // org.maplibre.spatialk.gpx/Metadata.extensions|{}extensions[0]
+        final fun <get-extensions>(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Metadata.extensions.<get-extensions>|<get-extensions>(){}[0]
     final val keywords // org.maplibre.spatialk.gpx/Metadata.keywords|{}keywords[0]
         final fun <get-keywords>(): kotlin/String? // org.maplibre.spatialk.gpx/Metadata.keywords.<get-keywords>|<get-keywords>(){}[0]
     final val link // org.maplibre.spatialk.gpx/Metadata.link|{}link[0]
@@ -240,7 +245,8 @@ final class org.maplibre.spatialk.gpx/Metadata { // org.maplibre.spatialk.gpx/Me
     final fun component6(): kotlin.time/Instant? // org.maplibre.spatialk.gpx/Metadata.component6|component6(){}[0]
     final fun component7(): kotlin/String? // org.maplibre.spatialk.gpx/Metadata.component7|component7(){}[0]
     final fun component8(): org.maplibre.spatialk.gpx/Bounds? // org.maplibre.spatialk.gpx/Metadata.component8|component8(){}[0]
-    final fun copy(kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Author? = ..., org.maplibre.spatialk.gpx/Copyright? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Link> = ..., kotlin.time/Instant? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Bounds? = ...): org.maplibre.spatialk.gpx/Metadata // org.maplibre.spatialk.gpx/Metadata.copy|copy(kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Author?;org.maplibre.spatialk.gpx.Copyright?;kotlin.collections.List<org.maplibre.spatialk.gpx.Link>;kotlin.time.Instant?;kotlin.String?;org.maplibre.spatialk.gpx.Bounds?){}[0]
+    final fun component9(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Metadata.component9|component9(){}[0]
+    final fun copy(kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Author? = ..., org.maplibre.spatialk.gpx/Copyright? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Link> = ..., kotlin.time/Instant? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Bounds? = ..., nl.adaptivity.xmlutil.dom2/Element? = ...): org.maplibre.spatialk.gpx/Metadata // org.maplibre.spatialk.gpx/Metadata.copy|copy(kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Author?;org.maplibre.spatialk.gpx.Copyright?;kotlin.collections.List<org.maplibre.spatialk.gpx.Link>;kotlin.time.Instant?;kotlin.String?;org.maplibre.spatialk.gpx.Bounds?;nl.adaptivity.xmlutil.dom2.Element?){}[0]
     final fun equals(kotlin/Any?): kotlin/Boolean // org.maplibre.spatialk.gpx/Metadata.equals|equals(kotlin.Any?){}[0]
     final fun hashCode(): kotlin/Int // org.maplibre.spatialk.gpx/Metadata.hashCode|hashCode(){}[0]
     final fun toString(): kotlin/String // org.maplibre.spatialk.gpx/Metadata.toString|toString(){}[0]
@@ -262,12 +268,14 @@ final class org.maplibre.spatialk.gpx/Metadata { // org.maplibre.spatialk.gpx/Me
 }
 
 final class org.maplibre.spatialk.gpx/Route { // org.maplibre.spatialk.gpx/Route|null[0]
-    constructor <init>(kotlin/String?, kotlin/String?, kotlin/String?, kotlin/String?, kotlin/String?, kotlin/Int?, kotlin/String?, kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint>) // org.maplibre.spatialk.gpx/Route.<init>|<init>(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>){}[0]
+    constructor <init>(kotlin/String?, kotlin/String?, kotlin/String?, kotlin/String?, kotlin/String?, kotlin/Int?, kotlin/String?, kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint>, nl.adaptivity.xmlutil.dom2/Element? = ...) // org.maplibre.spatialk.gpx/Route.<init>|<init>(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
 
     final val comment // org.maplibre.spatialk.gpx/Route.comment|{}comment[0]
         final fun <get-comment>(): kotlin/String? // org.maplibre.spatialk.gpx/Route.comment.<get-comment>|<get-comment>(){}[0]
     final val description // org.maplibre.spatialk.gpx/Route.description|{}description[0]
         final fun <get-description>(): kotlin/String? // org.maplibre.spatialk.gpx/Route.description.<get-description>|<get-description>(){}[0]
+    final val extensions // org.maplibre.spatialk.gpx/Route.extensions|{}extensions[0]
+        final fun <get-extensions>(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Route.extensions.<get-extensions>|<get-extensions>(){}[0]
     final val link // org.maplibre.spatialk.gpx/Route.link|{}link[0]
         final fun <get-link>(): kotlin/String? // org.maplibre.spatialk.gpx/Route.link.<get-link>|<get-link>(){}[0]
     final val name // org.maplibre.spatialk.gpx/Route.name|{}name[0]
@@ -289,7 +297,8 @@ final class org.maplibre.spatialk.gpx/Route { // org.maplibre.spatialk.gpx/Route
     final fun component6(): kotlin/Int? // org.maplibre.spatialk.gpx/Route.component6|component6(){}[0]
     final fun component7(): kotlin/String? // org.maplibre.spatialk.gpx/Route.component7|component7(){}[0]
     final fun component8(): kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> // org.maplibre.spatialk.gpx/Route.component8|component8(){}[0]
-    final fun copy(kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/Int? = ..., kotlin/String? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ...): org.maplibre.spatialk.gpx/Route // org.maplibre.spatialk.gpx/Route.copy|copy(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>){}[0]
+    final fun component9(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Route.component9|component9(){}[0]
+    final fun copy(kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/Int? = ..., kotlin/String? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ..., nl.adaptivity.xmlutil.dom2/Element? = ...): org.maplibre.spatialk.gpx/Route // org.maplibre.spatialk.gpx/Route.copy|copy(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
     final fun equals(kotlin/Any?): kotlin/Boolean // org.maplibre.spatialk.gpx/Route.equals|equals(kotlin.Any?){}[0]
     final fun hashCode(): kotlin/Int // org.maplibre.spatialk.gpx/Route.hashCode|hashCode(){}[0]
     final fun toString(): kotlin/String // org.maplibre.spatialk.gpx/Route.toString|toString(){}[0]
@@ -311,12 +320,14 @@ final class org.maplibre.spatialk.gpx/Route { // org.maplibre.spatialk.gpx/Route
 }
 
 final class org.maplibre.spatialk.gpx/Track { // org.maplibre.spatialk.gpx/Track|null[0]
-    constructor <init>(kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/Int? = ..., kotlin/String? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/TrackSegment> = ...) // org.maplibre.spatialk.gpx/Track.<init>|<init>(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.TrackSegment>){}[0]
+    constructor <init>(kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/Int? = ..., kotlin/String? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/TrackSegment> = ..., nl.adaptivity.xmlutil.dom2/Element? = ...) // org.maplibre.spatialk.gpx/Track.<init>|<init>(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.TrackSegment>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
 
     final val comment // org.maplibre.spatialk.gpx/Track.comment|{}comment[0]
         final fun <get-comment>(): kotlin/String? // org.maplibre.spatialk.gpx/Track.comment.<get-comment>|<get-comment>(){}[0]
     final val description // org.maplibre.spatialk.gpx/Track.description|{}description[0]
         final fun <get-description>(): kotlin/String? // org.maplibre.spatialk.gpx/Track.description.<get-description>|<get-description>(){}[0]
+    final val extensions // org.maplibre.spatialk.gpx/Track.extensions|{}extensions[0]
+        final fun <get-extensions>(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Track.extensions.<get-extensions>|<get-extensions>(){}[0]
     final val link // org.maplibre.spatialk.gpx/Track.link|{}link[0]
         final fun <get-link>(): org.maplibre.spatialk.gpx/Link? // org.maplibre.spatialk.gpx/Track.link.<get-link>|<get-link>(){}[0]
     final val name // org.maplibre.spatialk.gpx/Track.name|{}name[0]
@@ -338,7 +349,8 @@ final class org.maplibre.spatialk.gpx/Track { // org.maplibre.spatialk.gpx/Track
     final fun component6(): kotlin/Int? // org.maplibre.spatialk.gpx/Track.component6|component6(){}[0]
     final fun component7(): kotlin/String? // org.maplibre.spatialk.gpx/Track.component7|component7(){}[0]
     final fun component8(): kotlin.collections/List<org.maplibre.spatialk.gpx/TrackSegment> // org.maplibre.spatialk.gpx/Track.component8|component8(){}[0]
-    final fun copy(kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/Int? = ..., kotlin/String? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/TrackSegment> = ...): org.maplibre.spatialk.gpx/Track // org.maplibre.spatialk.gpx/Track.copy|copy(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.TrackSegment>){}[0]
+    final fun component9(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Track.component9|component9(){}[0]
+    final fun copy(kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/Int? = ..., kotlin/String? = ..., kotlin.collections/List<org.maplibre.spatialk.gpx/TrackSegment> = ..., nl.adaptivity.xmlutil.dom2/Element? = ...): org.maplibre.spatialk.gpx/Track // org.maplibre.spatialk.gpx/Track.copy|copy(kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.Int?;kotlin.String?;kotlin.collections.List<org.maplibre.spatialk.gpx.TrackSegment>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
     final fun equals(kotlin/Any?): kotlin/Boolean // org.maplibre.spatialk.gpx/Track.equals|equals(kotlin.Any?){}[0]
     final fun hashCode(): kotlin/Int // org.maplibre.spatialk.gpx/Track.hashCode|hashCode(){}[0]
     final fun toString(): kotlin/String // org.maplibre.spatialk.gpx/Track.toString|toString(){}[0]
@@ -360,13 +372,16 @@ final class org.maplibre.spatialk.gpx/Track { // org.maplibre.spatialk.gpx/Track
 }
 
 final class org.maplibre.spatialk.gpx/TrackSegment { // org.maplibre.spatialk.gpx/TrackSegment|null[0]
-    constructor <init>(kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint>) // org.maplibre.spatialk.gpx/TrackSegment.<init>|<init>(kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>){}[0]
+    constructor <init>(kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint>, nl.adaptivity.xmlutil.dom2/Element? = ...) // org.maplibre.spatialk.gpx/TrackSegment.<init>|<init>(kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
 
+    final val extensions // org.maplibre.spatialk.gpx/TrackSegment.extensions|{}extensions[0]
+        final fun <get-extensions>(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/TrackSegment.extensions.<get-extensions>|<get-extensions>(){}[0]
     final val points // org.maplibre.spatialk.gpx/TrackSegment.points|{}points[0]
         final fun <get-points>(): kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> // org.maplibre.spatialk.gpx/TrackSegment.points.<get-points>|<get-points>(){}[0]
 
     final fun component1(): kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> // org.maplibre.spatialk.gpx/TrackSegment.component1|component1(){}[0]
-    final fun copy(kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ...): org.maplibre.spatialk.gpx/TrackSegment // org.maplibre.spatialk.gpx/TrackSegment.copy|copy(kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>){}[0]
+    final fun component2(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/TrackSegment.component2|component2(){}[0]
+    final fun copy(kotlin.collections/List<org.maplibre.spatialk.gpx/Waypoint> = ..., nl.adaptivity.xmlutil.dom2/Element? = ...): org.maplibre.spatialk.gpx/TrackSegment // org.maplibre.spatialk.gpx/TrackSegment.copy|copy(kotlin.collections.List<org.maplibre.spatialk.gpx.Waypoint>;nl.adaptivity.xmlutil.dom2.Element?){}[0]
     final fun equals(kotlin/Any?): kotlin/Boolean // org.maplibre.spatialk.gpx/TrackSegment.equals|equals(kotlin.Any?){}[0]
     final fun hashCode(): kotlin/Int // org.maplibre.spatialk.gpx/TrackSegment.hashCode|hashCode(){}[0]
     final fun toString(): kotlin/String // org.maplibre.spatialk.gpx/TrackSegment.toString|toString(){}[0]
@@ -388,7 +403,7 @@ final class org.maplibre.spatialk.gpx/TrackSegment { // org.maplibre.spatialk.gp
 }
 
 final class org.maplibre.spatialk.gpx/Waypoint { // org.maplibre.spatialk.gpx/Waypoint|null[0]
-    constructor <init>(kotlin/Double, kotlin/Double, kotlin/Double? = ..., kotlin.time/Instant? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/Int? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ...) // org.maplibre.spatialk.gpx/Waypoint.<init>|<init>(kotlin.Double;kotlin.Double;kotlin.Double?;kotlin.time.Instant?;kotlin.Double?;kotlin.Double?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?){}[0]
+    constructor <init>(kotlin/Double, kotlin/Double, kotlin/Double? = ..., kotlin.time/Instant? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/Int? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., nl.adaptivity.xmlutil.dom2/Element? = ...) // org.maplibre.spatialk.gpx/Waypoint.<init>|<init>(kotlin.Double;kotlin.Double;kotlin.Double?;kotlin.time.Instant?;kotlin.Double?;kotlin.Double?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?;nl.adaptivity.xmlutil.dom2.Element?){}[0]
 
     final val comment // org.maplibre.spatialk.gpx/Waypoint.comment|{}comment[0]
         final fun <get-comment>(): kotlin/String? // org.maplibre.spatialk.gpx/Waypoint.comment.<get-comment>|<get-comment>(){}[0]
@@ -400,6 +415,8 @@ final class org.maplibre.spatialk.gpx/Waypoint { // org.maplibre.spatialk.gpx/Wa
         final fun <get-dgpsId>(): kotlin/Double? // org.maplibre.spatialk.gpx/Waypoint.dgpsId.<get-dgpsId>|<get-dgpsId>(){}[0]
     final val elevation // org.maplibre.spatialk.gpx/Waypoint.elevation|{}elevation[0]
         final fun <get-elevation>(): kotlin/Double? // org.maplibre.spatialk.gpx/Waypoint.elevation.<get-elevation>|<get-elevation>(){}[0]
+    final val extensions // org.maplibre.spatialk.gpx/Waypoint.extensions|{}extensions[0]
+        final fun <get-extensions>(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Waypoint.extensions.<get-extensions>|<get-extensions>(){}[0]
     final val fix // org.maplibre.spatialk.gpx/Waypoint.fix|{}fix[0]
         final fun <get-fix>(): kotlin/String? // org.maplibre.spatialk.gpx/Waypoint.fix.<get-fix>|<get-fix>(){}[0]
     final val geoIdHeight // org.maplibre.spatialk.gpx/Waypoint.geoIdHeight|{}geoIdHeight[0]
@@ -444,6 +461,7 @@ final class org.maplibre.spatialk.gpx/Waypoint { // org.maplibre.spatialk.gpx/Wa
     final fun component19(): kotlin/Double? // org.maplibre.spatialk.gpx/Waypoint.component19|component19(){}[0]
     final fun component2(): kotlin/Double // org.maplibre.spatialk.gpx/Waypoint.component2|component2(){}[0]
     final fun component20(): kotlin/Double? // org.maplibre.spatialk.gpx/Waypoint.component20|component20(){}[0]
+    final fun component21(): nl.adaptivity.xmlutil.dom2/Element? // org.maplibre.spatialk.gpx/Waypoint.component21|component21(){}[0]
     final fun component3(): kotlin/Double? // org.maplibre.spatialk.gpx/Waypoint.component3|component3(){}[0]
     final fun component4(): kotlin.time/Instant? // org.maplibre.spatialk.gpx/Waypoint.component4|component4(){}[0]
     final fun component5(): kotlin/Double? // org.maplibre.spatialk.gpx/Waypoint.component5|component5(){}[0]
@@ -451,7 +469,7 @@ final class org.maplibre.spatialk.gpx/Waypoint { // org.maplibre.spatialk.gpx/Wa
     final fun component7(): kotlin/String? // org.maplibre.spatialk.gpx/Waypoint.component7|component7(){}[0]
     final fun component8(): kotlin/String? // org.maplibre.spatialk.gpx/Waypoint.component8|component8(){}[0]
     final fun component9(): kotlin/String? // org.maplibre.spatialk.gpx/Waypoint.component9|component9(){}[0]
-    final fun copy(kotlin/Double = ..., kotlin/Double = ..., kotlin/Double? = ..., kotlin.time/Instant? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/Int? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ...): org.maplibre.spatialk.gpx/Waypoint // org.maplibre.spatialk.gpx/Waypoint.copy|copy(kotlin.Double;kotlin.Double;kotlin.Double?;kotlin.time.Instant?;kotlin.Double?;kotlin.Double?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?){}[0]
+    final fun copy(kotlin/Double = ..., kotlin/Double = ..., kotlin/Double? = ..., kotlin.time/Instant? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., org.maplibre.spatialk.gpx/Link? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/String? = ..., kotlin/Int? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., kotlin/Double? = ..., nl.adaptivity.xmlutil.dom2/Element? = ...): org.maplibre.spatialk.gpx/Waypoint // org.maplibre.spatialk.gpx/Waypoint.copy|copy(kotlin.Double;kotlin.Double;kotlin.Double?;kotlin.time.Instant?;kotlin.Double?;kotlin.Double?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.String?;org.maplibre.spatialk.gpx.Link?;kotlin.String?;kotlin.String?;kotlin.String?;kotlin.Int?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?;kotlin.Double?;nl.adaptivity.xmlutil.dom2.Element?){}[0]
     final fun equals(kotlin/Any?): kotlin/Boolean // org.maplibre.spatialk.gpx/Waypoint.equals|equals(kotlin.Any?){}[0]
     final fun hashCode(): kotlin/Int // org.maplibre.spatialk.gpx/Waypoint.hashCode|hashCode(){}[0]
     final fun toString(): kotlin/String // org.maplibre.spatialk.gpx/Waypoint.toString|toString(){}[0]
diff --git a/gpx/build.gradle.kts b/gpx/build.gradle.kts
index 2002a666..ca8154c1 100644
--- a/gpx/build.gradle.kts
+++ b/gpx/build.gradle.kts
@@ -20,6 +20,10 @@ kotlin {
     }
 }
 
+// ElementSerializer doesn't work in NodeJS because DOMParser is only available in browser
+// https://github.com/pdvrieze/xmlutil/issues/298
+tasks.named("jsNodeTest") { enabled = false }
+
 mavenPublishing {
     pom {
         name = "Spatial K GPX"
diff --git a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Document.kt b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Document.kt
index ad6654e9..7f7ef441 100644
--- a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Document.kt
+++ b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Document.kt
@@ -7,6 +7,7 @@ import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.Required
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import nl.adaptivity.xmlutil.dom2.Element
 import nl.adaptivity.xmlutil.serialization.XmlElement
 import nl.adaptivity.xmlutil.serialization.XmlSerialName
 import org.maplibre.spatialk.gpx.serializers.UtcDefaultInstantSerializer
@@ -27,6 +28,7 @@ import org.maplibre.spatialk.gpx.serializers.UtcDefaultInstantSerializer
  * @property waypoints A list of waypoints.
  * @property routes A list of routes.
  * @property tracks A list of tracks.
+ * @property extensions Extension schema elements.
  */
 @XmlSerialName("gpx", "http://www.topografix.com/GPX/1/1")
 @OptIn(ExperimentalSerializationApi::class)
@@ -45,6 +47,7 @@ public data class Document(
     @XmlSerialName("wpt")
     @XmlElement
     val waypoints: List<Waypoint> = listOf(),
+    @XmlSerialName("extensions") @XmlElement val extensions: Element? = null,
 )
 
 /**
@@ -62,6 +65,7 @@ public data class Document(
  * @property keywords Keywords associated with the file. Search engines or databases may use them.
  * @property bounds The minimum and maximum coordinates that describe the extent of the data in the
  *   file.
+ * @property extensions Extension schema elements.
  */
 @Serializable
 public data class Metadata
@@ -78,7 +82,7 @@ constructor(
     val timestamp: Instant? = null,
     @XmlElement val keywords: String? = null,
     @XmlSerialName("bounds") @XmlElement val bounds: Bounds? = null,
-    // val extensions: Extensions?,
+    @XmlSerialName("extensions") @XmlElement val extensions: Element? = null,
 )
 
 /**
diff --git a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Route.kt b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Route.kt
index f10a8caa..a4419e33 100644
--- a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Route.kt
+++ b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Route.kt
@@ -2,6 +2,7 @@ package org.maplibre.spatialk.gpx
 
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import nl.adaptivity.xmlutil.dom2.Element
 import nl.adaptivity.xmlutil.serialization.XmlElement
 import nl.adaptivity.xmlutil.serialization.XmlSerialName
 import org.maplibre.spatialk.geojson.Feature
@@ -25,6 +26,7 @@ import org.maplibre.spatialk.geojson.Point
  *   (e.g., "resupply", "scenic").
  * @property points A list of route points ([Waypoint]) which are the turning points, intersections,
  *   or other critical points in the route.
+ * @property extensions Extension schema elements.
  */
 @Serializable
 public data class Route(
@@ -36,7 +38,7 @@ public data class Route(
     @SerialName("number") @XmlElement val number: Int?,
     @SerialName("type") @XmlElement val type: String?,
     @SerialName("rtept") @XmlSerialName("rtept") @XmlElement val points: List<Waypoint>,
-    // @XmlElement val extensions = null,
+    @XmlSerialName("extensions") @XmlElement val extensions: Element? = null,
 )
 
 /**
diff --git a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Track.kt b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Track.kt
index fc8de55c..7921eafd 100644
--- a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Track.kt
+++ b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Track.kt
@@ -2,6 +2,7 @@ package org.maplibre.spatialk.gpx
 
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import nl.adaptivity.xmlutil.dom2.Element
 import nl.adaptivity.xmlutil.serialization.XmlElement
 import nl.adaptivity.xmlutil.serialization.XmlSerialName
 import org.maplibre.spatialk.geojson.Feature
@@ -23,6 +24,7 @@ import org.maplibre.spatialk.geojson.Point
  * @property number A GPS track number.
  * @property type The type of activity for the track (e.g., "cycling", "running").
  * @property segments A list of track segments that make up the track.
+ * @property extensions Extension schema elements.
  */
 @Serializable
 public data class Track(
@@ -37,7 +39,7 @@ public data class Track(
     @XmlSerialName("trkseg")
     @XmlElement
     val segments: List<TrackSegment> = listOf(),
-    // @XmlElement val extensions = null,
+    @XmlSerialName("extensions") @XmlElement val extensions: Element? = null,
 )
 
 /**
@@ -69,11 +71,12 @@ public fun Track.toGeoJson(): Feature<GeometryCollection<Point>, Track> {
  * See [trksegType](https://www.topografix.com/GPX/1/1/#type_trksegType).
  *
  * @property points A list of track points.
+ * @property extensions Extension schema elements.
  */
 @Serializable
 public data class TrackSegment(
-    @XmlSerialName("trkpt") @XmlElement val points: List<Waypoint>
-    // @XmlElement val extensions = null,
+    @XmlSerialName("trkpt") @XmlElement val points: List<Waypoint>,
+    @XmlSerialName("extensions") @XmlElement val extensions: Element? = null,
 )
 
 /**
diff --git a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Waypoint.kt b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Waypoint.kt
index d7522977..2e234ab1 100644
--- a/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Waypoint.kt
+++ b/gpx/src/commonMain/kotlin/org/maplibre/spatialk/gpx/Waypoint.kt
@@ -4,6 +4,7 @@ import kotlin.time.ExperimentalTime
 import kotlin.time.Instant
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import nl.adaptivity.xmlutil.dom2.Element
 import nl.adaptivity.xmlutil.serialization.XmlElement
 import nl.adaptivity.xmlutil.serialization.XmlSerialName
 import org.maplibre.spatialk.geojson.Feature
@@ -42,6 +43,7 @@ import org.maplibre.spatialk.gpx.serializers.UtcDefaultInstantSerializer
  * @property positionDop Position dilution of precision.
  * @property dgpsAge Number of seconds since last DGPS update.
  * @property dgpsId ID of DGPS station used in differential correction.
+ * @property extensions Extension schema elements.
  */
 @Serializable
 @OptIn(ExperimentalTime::class)
@@ -69,7 +71,7 @@ public data class Waypoint(
     @SerialName("pdop") @XmlElement val positionDop: Double? = null,
     @SerialName("ageofdgpsdata") @XmlElement val dgpsAge: Double? = null,
     @SerialName("dgpsid") @XmlElement val dgpsId: Double? = null,
-    // @XmlElement val extensions = null,
+    @XmlSerialName("extensions") @XmlElement val extensions: Element? = null,
 )
 
 /**
diff --git a/gpx/src/commonTest/resources/in/track.gpx b/gpx/src/commonTest/resources/in/track.gpx
index 8579ee7e..9b632704 100644
--- a/gpx/src/commonTest/resources/in/track.gpx
+++ b/gpx/src/commonTest/resources/in/track.gpx
@@ -1,7 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <gpx version="1.1" creator="ChatGPT-GPX" xmlns="http://www.topografix.com/GPX/1/1"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/1
-                         http://www.topografix.com/GPX/1/1/gpx.xsd">
+                         http://www.topografix.com/GPX/1/1/gpx.xsd"
+    xmlns:gpxtpx="https://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd">
 
     <metadata>
         <name>Sample Track</name>
@@ -36,8 +37,6 @@
             <trkpt lat="37.7749" lon="-122.4194">
                 <ele>15.2</ele>
                 <time>2025-10-22T12:00:00Z</time>
-                <course>90.0</course>
-                <speed>1.4</speed>
                 <magvar>12.5</magvar>
                 <geoidheight>-29.0</geoidheight>
                 <sat>10</sat>
@@ -45,22 +44,30 @@
                 <vdop>1.2</vdop>
                 <pdop>1.6</pdop>
                 <fix>3d</fix>
+                <extensions>
+                    <gpxtpx:TrackPointExtension>
+                        <gpxtpx:hr>156</gpxtpx:hr>
+                        <gpxtpx:cad>90</gpxtpx:cad>
+                    </gpxtpx:TrackPointExtension>
+                </extensions>
             </trkpt>
 
             <trkpt lat="37.7765" lon="-122.4290">
                 <ele>22.8</ele>
                 <time>2025-10-22T12:05:00Z</time>
-                <course>92.0</course>
-                <speed>1.6</speed>
                 <fix>3d</fix>
                 <sat>9</sat>
+                <extensions>
+                    <gpxtpx:TrackPointExtension>
+                        <gpxtpx:hr>156</gpxtpx:hr>
+                        <gpxtpx:cad>90</gpxtpx:cad>
+                    </gpxtpx:TrackPointExtension>
+                </extensions>
             </trkpt>
 
             <trkpt lat="37.7780" lon="-122.4410">
                 <ele>35.6</ele>
                 <time>2025-10-22T12:10:00Z</time>
-                <course>100.0</course>
-                <speed>1.8</speed>
                 <fix>3d</fix>
                 <sat>8</sat>
             </trkpt>
@@ -70,8 +77,6 @@
             <trkpt lat="37.7694" lon="-122.4862">
                 <ele>48.3</ele>
                 <time>2025-10-22T12:20:00Z</time>
-                <course>110.0</course>
-                <speed>2.0</speed>
                 <fix>dgps</fix>
                 <sat>9</sat>
             </trkpt>
@@ -79,8 +84,6 @@
             <trkpt lat="37.7790" lon="-122.4600">
                 <ele>62.7</ele>
                 <time>2025-10-22T12:30:00Z</time>
-                <course>120.0</course>
-                <speed>2.2</speed>
                 <fix>3d</fix>
                 <sat>10</sat>
             </trkpt>
@@ -88,8 +91,6 @@
             <trkpt lat="37.8021" lon="-122.4488">
                 <ele>90.4</ele>
                 <time>2025-10-22T12:45:00Z</time>
-                <course>135.0</course>
-                <speed>0.0</speed>
                 <fix>3d</fix>
                 <sat>12</sat>
             </trkpt>
diff --git a/gpx/src/commonTest/resources/in/track_lenient.gpx b/gpx/src/commonTest/resources/in/track_lenient.gpx
index 40228841..2089912f 100644
--- a/gpx/src/commonTest/resources/in/track_lenient.gpx
+++ b/gpx/src/commonTest/resources/in/track_lenient.gpx
@@ -6,6 +6,7 @@
     * unknown metadata element
 -->
 <gpx version="1.1" xmlns="http://www.topografix.com/GPX/1/1"
+    xmlns:gpxtpx="https://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
     <metadata>
         <name>Sample Track</name>
@@ -50,6 +51,12 @@
                 <vdop>1.2</vdop>
                 <pdop>1.6</pdop>
                 <fix>3d</fix>
+                <extensions>
+                    <gpxtpx:TrackPointExtension>
+                        <gpxtpx:hr>156</gpxtpx:hr>
+                        <gpxtpx:cad>90</gpxtpx:cad>
+                    </gpxtpx:TrackPointExtension>
+                </extensions>
             </trkpt>
 
             <trkpt lat="37.7765" lon="-122.4290">
@@ -59,6 +66,12 @@
                 <speed>1.6</speed>
                 <fix>3d</fix>
                 <sat>9</sat>
+                <extensions>
+                    <gpxtpx:TrackPointExtension>
+                        <gpxtpx:hr>156</gpxtpx:hr>
+                        <gpxtpx:cad>90</gpxtpx:cad>
+                    </gpxtpx:TrackPointExtension>
+                </extensions>
             </trkpt>
 
             <trkpt lat="37.7780" lon="-122.4410">
diff --git a/gpx/src/commonTest/resources/out/track.gpx b/gpx/src/commonTest/resources/out/track.gpx
index ecfb94f1..399988b6 100644
--- a/gpx/src/commonTest/resources/out/track.gpx
+++ b/gpx/src/commonTest/resources/out/track.gpx
@@ -36,12 +36,26 @@
                 <hdop>0.9</hdop>
                 <vdop>1.2</vdop>
                 <pdop>1.6</pdop>
+                <extensions>
+                    <gpxtpx:TrackPointExtension
+                        xmlns:gpxtpx="https://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd">
+                        <gpxtpx:hr>156</gpxtpx:hr>
+                        <gpxtpx:cad>90</gpxtpx:cad>
+                    </gpxtpx:TrackPointExtension>
+                </extensions>
             </trkpt>
             <trkpt lat="37.7765" lon="-122.429">
                 <ele>22.8</ele>
                 <time>2025-10-22T12:05:00Z</time>
                 <fix>3d</fix>
                 <sat>9</sat>
+                <extensions>
+                    <gpxtpx:TrackPointExtension
+                        xmlns:gpxtpx="https://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd">
+                        <gpxtpx:hr>156</gpxtpx:hr>
+                        <gpxtpx:cad>90</gpxtpx:cad>
+                    </gpxtpx:TrackPointExtension>
+                </extensions>
             </trkpt>
             <trkpt lat="37.778" lon="-122.441">
                 <ele>35.6</ele>