Detailed list of Disk Cleanup, and able to use it as a Configuration?

Detailed list of Disk Cleanup, and able to use it as a Configuration?

Is there a detailed list of descriptions of the Disk Cleanup items?  I see "old chkdsk files", but is that a raw "*.chk" anywhere on the drive, or the checkbox option on cleanupmgr?  Same goes for Service Pack Cleanup and Windows Update Cleanup.  It isn't particularly clear what those do - is either a dism cleanup command?

For that matter, does that simply invoke cleanupmgr, or does it run it's own thing?  Many of the machines I support don't have cleanupmgr installed.

Lastly, is there a way to use the Disk Cleanup as a Configuration?  That way I can run it on-demand, for instance.