Documentation Version
You're reading the documentation for the non-stable development version of MoveIt 2. For the stable, released version, please have a look at Humble.
How To Generate API Doxygen Reference Locally
Run doxygen in the root of the moveit2 repository.
Steps
Navigate to the moveit2 repository:
cd ~/ws_moveit/src/moveit2
Run reference generation command with desired output directory path:
DOXYGEN_OUTPUT_DIRECTORY=~/docs doxygen
The documentation entrypoint in a browser is index.html which you can access with:
firefox ~/docs/index.html