$ git clone -n https://src.fedoraproject.org/rpms/libplacebo.git /var/lib/mock/f39-build-1864672-42538/root/chroot_tmpdir/scmroot/libplacebo
Cloning into '/var/lib/mock/f39-build-1864672-42538/root/chroot_tmpdir/scmroot/libplacebo'...
$ git fetch origin 49e830602e6913339fb4d0f0a5bca617ee450507:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libplacebo
 * [new ref]         49e830602e6913339fb4d0f0a5bca617ee450507 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 49e8306 Revert "Update to 6.338.0"