This is libxml2, packaged for Zig.
First, update your build.zig.zon:
# Initialize a `zig build` project if you haven't already
zig init
zig fetch --save git+https://github.com/allyourcodebase/libxml2.git#2.14.3-4
You can then import libxml2 in your build.zig with:
const libxml2_dependency = b.dependency("libxml2", .{
    .target = target,
    .optimize = optimize,
    // libxml2 will try to link to iconv on macOS by default which will
    // fail when cross-compiling. You may disable iconv support for or
    // link against GNU libiconv which is licensed under LGPL.
    // disable iconv support on all targets
    // .iconv = false,
    // disable iconv support when compiling to macOS
    // .iconv = !target.result.os.tag.isDarwin(),
    // disable iconv support when cross-compiling to macOS
    // .iconv = !(target.query.isNativeOs() and target.result.os.tag.isDarwin()),
    // Use GNU libiconv on macOS which is licensed under LGPL.
    // .@"iconv-impl" = if (target.result.os.tag.isDarwin()) else null,
});
your_exe.linkLibrary(libxml2_dependency.artifact("xml"));