Confusing sentence in Cookbook on Server caching

The documentation states:
> QGIS server maintains a cache of the capabilities then to have a cache per role you can return the role in this method. Or return None to completely disable the cache.

Not sure of what is meant there.
Page URL: https://docs.qgis.org/3.28/en/docs/pyqgis_developer_cookbook/server.html#cachekey
