MarsSeed [1] filed a deletion request for mutagen-git [2]: Deprecated VCS package, it was deleted, seems it has been pushed back by accident.
Not needed, the proper package is this: https://aur.archlinux.org/packages/python-mutagen-git [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/mutagen-git/
