Ron, part of that is the fun of Windchill!!
Okay in more seriousness.
I reversed engineered / debugged those advanced objects awhile back and they
do not give much, the key is looking at what default one is utilized to gain
basic functionality. If I recall without looking, operation was to tell the
LWC API how to treat it, create, read, update, delete (but I could be wrong
until I examined it again).
Technically, R&D can help customization TSE's explain this for you if you
have a real need if it is flagged as supported API. Keep in mind that just
because the object is flagged as supported doesn't mean all of the input
objects are.
Perhaps you can shed light on why you want to know what it does? Most folks
are happy with the info made available. If they were to provide more
documentation, more folks would just ask why. (Kind of sometimes like why
did they design that part in my car so poorly.)