micwoj92 [1] filed a deletion request for msgpack-erlang [2]: 0 votes, 0 comments, orphan. Upstream seems barely maintained and latest 0.8.1 release fails to build with erlang/OTP 27.
[1] https://aur.archlinux.org/account/micwoj92/ [2] https://aur.archlinux.org/pkgbase/msgpack-erlang/
