Mapbender3 offers an API documentation at http://api.mapbender3.org/.
ApiGen is used to generate API documentation. ‘All’ you have to do is to insert docblocks in your code. Below you find an example class with docbblock annotations:
Have a look at the docblocks at `Example.php<https://github.com/mapbender/mapbender-documentation/blob/master/de/book/development/Example.php>`_.
This has not yet been decided as good tools are almost not to be found.