Eli & Lars, as a point of clarification: what would you want to see in terms of integration into core for use-package to make the late-November cut for emacs 29.1?
My understanding is that the copyright concerns are cleared, but John (Weigley, for anyone looking at this later) believes that some documentation work needs to be done. He doesn't have time to do it himself, but there do seem to be some potential volunteers (tentatively including myself).
I expect that _eventually_ relatively deep documentation changes would be wanted if it were included in core (both to use-package and to emacs's existing documentation), but that it might be ok to include the package (with correct documentation) in 29.1 without necessarily pushing it throughout all of emacs' own documentation. Does that sound reasonable?