MarsSeed [1] filed a deletion request for downgrader-git [2]:
I think this legacy VCS package is not needed.
Code development halted in 2017; also no alive forks exist.
Its corresponding non-VCS package has already been deleted: https://aur.archlinux.org/packages/downgrader/
This application should not be confused with AUR/downgrade: https://aur.archlinux.org/packages/downgrade
That is a completely different code (downgrader is C, downgrade is shell script based).
The 'downgrade' project is alive and well, so that package should be kept.
In contrast, this downgrader-git should be deleted because it is defunct and not useful to have a package for it. I wouldn't think it can be stable and safe, given that it uses pacman which has seen API changes and at least one major version bump (from v5 to v6) during the past 5 years.
Nothing depends on this package and last user comments are from 2018, so it seems safe to delete.
[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/downgrader-git/