MarsSeed [1] filed a deletion request for ostree-git [2]: Broken, unused VCS package from 2020.
Repo carries the stable release. [a] [a]: https://archlinux.org/packages/?q=ostree [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/ostree-git/