simple_2_link.urdf is vendored from the Isaac Lab project:

  Source:  https://github.com/isaac-sim/IsaacLab
  Path:    source/isaaclab/test/sensors/urdfs/simple_2_link.urdf
  Commit:  b4c3210
  License: BSD-3-Clause

Copyright (c) 2022-2026, The Isaac Lab Project Developers.
All rights reserved.

Redistributed under the BSD-3-Clause license. See the Isaac Lab repository
for the full license text. Used here, unmodified, as a CI parity-test fixture.
