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To look at these, examine all user profiles to see what special authority they have, and what groups they belong to.
Examine each object to determine what userids and group profiles have authority to "object exist" on the objects. Also identify to see what object authroization list might be associated with the a given object.
DSPUSRPRF USRPRF(*ALL) output(outfile) outfile(yourlib/yourfilename) will dump a listing of all user ids, their special authority and group profiles to a file that you specify ((yourlib/yourfilename) that you can query as to who has *allobj authority and determine what groups an id belongs to (note: there are to group profiles to look at: Group profile (upgrpf) and supplimental groups (upsupg).
Examine authorization lists from the authorization list menu (go cmdautl) (I can't think of a way to review users on an authorization list).
Actual objects authority, I don't see a way to dump data to a file so I think maybe you might need to do WRKOBJ obj(libname/*all) objtype(*all) (where the object is the specified object by name in this case library=libname and object name = *all will get all objects. Objtype you can use *file, *pgm, etc. to thin the list to more managable size.
Look at the authorization setting (option 5) on each object. Look for Object authority *all or *usrdef. If *usrdef, press F11 to see the user has object exist authority.
There are probably some 3rd party tools that will do this much cleaner.