Point README source links at permalinks where the upstream file moved

Author: rishabhsai

CONTRIBUTORS.md

@@ -40,6 +40,7 @@ Built by the Google DeepMind team with contributions from the open-source commun
 - [Nan Wang](https://github.com/Nan-Tetheria)
 - [Nikita Cherniadev](https://github.com/chernyadev)
 - [Omar Rayyan](https://github.com/omarrayyann)
+- [Rishabh Sai](https://github.com/rishabhsai)
 - [Sai Kishor Kothakota](https://github.com/saikishor)
 - [Taylor Howell](https://github.com/thowell)
 - [Thomas Lips](https://github.com/tlpss)

boston_dynamics_spot/CHANGELOG.md

@@ -2,5 +2,8 @@
 
 All notable changes to this model will be documented in this file.
 
+## [2026-09-12]
+- Point the `spot_ros2` URDF links in the README at the last commit before `spot_description` moved out of that repository.
+
 ## [2024-05-31]
 - Initial release.

boston_dynamics_spot/README.md

@@ -24,8 +24,8 @@ available URDF description](https://github.com/bdaiinstitute/spot_ros2).
 2. Added `<mujoco> <compiler discardvisual="false" strippath="false" fusestatic="false"/> </mujoco>` to the URDF's
    `<robot>` clause in order to preserve visual geometries.
 3. Loaded the URDF into MuJoCo and saved a corresponding MJCF.
-    * The spot XML was derived from [spot_simple.urdf.xacro](https://github.com/bdaiinstitute/spot_ros2/blob/main/spot_description/urdf/spot_simple.urdf.xacro).
-    * The arm XML was derived from [spot_arm_macro.urdf](https://github.com/bdaiinstitute/spot_ros2/blob/main/spot_description/urdf/spot_arm_macro.urdf).
+    * The spot XML was derived from [spot_simple.urdf.xacro](https://github.com/bdaiinstitute/spot_ros2/blob/56bffe846a70/spot_description/urdf/spot_simple.urdf.xacro).
+    * The arm XML was derived from [spot_arm_macro.urdf](https://github.com/bdaiinstitute/spot_ros2/blob/56bffe846a70/spot_description/urdf/spot_arm_macro.urdf).
 4. Added a `<freejoint/>` to the base, and a tracking light.
 5. Manually edited the MJCF to extract common properties into the `<default>` section.
 6. Added `<exclude>` clauses to prevent collisions between the base and the upper legs.

i2rt_yam/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to this model will be documented in this file.
 
+## [2026-09-12]
+
+- Point the YAM URDF link in the README at `d4efb66`, the revision step 1 already cites, since `robot_models/` moved upstream.
+
 ## [2025-05-19]
 
 - Initial release.

i2rt_yam/README.md

@@ -12,7 +12,7 @@ See [CHANGELOG.md](./CHANGELOG.md) for a full history of changes.
 This package contains a simplified robot description (MJCF) of the [YAM robot](https://i2rt.com/products/yam-manipulator) developed by [I2
 RT Robotics](https://i2rt.com/). It is derived from the [publicly available
 URDF
-description](https://github.com/i2rt-robotics/i2rt/blob/main/robot_models/yam/yam.urdf).
+description](https://github.com/i2rt-robotics/i2rt/blob/d4efb66d81bd8bde42909880b16591d4af82e8c0/robot_models/yam/yam.urdf).
 
 <p float="left">
   <img src="yam.png" width="400">

kuka_iiwa_14/CHANGELOG.md

@@ -2,5 +2,8 @@
 
 All notable changes to this model will be documented in this file.
 
+## [2026-09-12]
+- Point the Drake URDF links in the README at `v1.27.0`, the last release that ships `manipulation/models/iiwa_description`.
+
 ## [2023-05-18]
 - Initial release.

kuka_iiwa_14/README.md

@@ -10,7 +10,7 @@ See [CHANGELOG.md](./CHANGELOG.md) for a full history of changes.
 ## Overview
 
 This package contains a simplified robot description (MJCF) of the [LBR iiwa](https://www.kuka.com/en-us/products/robotics-systems/industrial-robots/lbr-iiwa) 14kg developed
-by [KUKA Robotics](https://www.kuka.com/en-us). It is derived from the [publicly available](https://github.com/RobotLocomotion/drake/blob/master/manipulation/models/iiwa_description/urdf/iiwa14_spheres_dense_collision.urdf)
+by [KUKA Robotics](https://www.kuka.com/en-us). It is derived from the [publicly available](https://github.com/RobotLocomotion/drake/blob/v1.27.0/manipulation/models/iiwa_description/urdf/iiwa14_spheres_dense_collision.urdf)
 URDF description created by the [Drake](https://github.com/RobotLocomotion/drake) developers.
 
 <p float="left">
@@ -20,7 +20,7 @@ URDF description created by the [Drake](https://github.com/RobotLocomotion/drake
 ## URDF → MJCF derivation steps
 
 1. Added `<mujoco> <compiler discardvisual="false"/> </mujoco>` to the
-   [URDF](https://github.com/RobotLocomotion/drake/blob/master/manipulation/models/iiwa_description/urdf/iiwa14_spheres_dense_collision.urdf)'s
+   [URDF](https://github.com/RobotLocomotion/drake/blob/v1.27.0/manipulation/models/iiwa_description/urdf/iiwa14_spheres_dense_collision.urdf)'s
    `<robot>` clause in order to preserve visual geometries.
 2. Loaded the URDF into MuJoCo and saved a corresponding MJCF.
 3. Created base body and added its corresponding inertial properties.

unitree_a1/CHANGELOG.md

@@ -2,5 +2,8 @@
 
 All notable changes to this model will be documented in this file.
 
+## [2026-09-12]
+- Point the `unitree_mujoco` URDF and mesh links in the README at the last commit that ships `data/a1`.
+
 ## [2022-09-07]
 - Initial release.

unitree_a1/README.md

@@ -13,7 +13,7 @@ This package contains a simplified robot description (MJCF) of the [A1 Quadruped
 Robot](https://www.unitree.com/a1/) developed by [Unitree
 Robotics](https://www.unitree.com/). It is derived from the [publicly available
 URDF
-description](https://github.com/unitreerobotics/unitree_mujoco/tree/main/data/a1/urdf).
+description](https://github.com/unitreerobotics/unitree_mujoco/tree/f3300ff1bf0a/data/a1/urdf).
 
 <p float="left">
   <img src="a1.png" width="400">
@@ -22,7 +22,7 @@ description](https://github.com/unitreerobotics/unitree_mujoco/tree/main/data/a1
 ## URDF → MJCF derivation steps
 
 1. Converted the DAE [mesh
-   files](https://github.com/unitreerobotics/unitree_mujoco/tree/main/data/a1/meshes)
+   files](https://github.com/unitreerobotics/unitree_mujoco/tree/f3300ff1bf0a/data/a1/meshes)
 to OBJ format using [Blender](https://www.blender.org/).
 2. Processed `.obj` files with [`obj2mjcf`](https://github.com/kevinzakka/obj2mjcf).
 3. Added `<mujoco> <compiler discardvisual="false"/> </mujoco>` to the URDF's