$ git clone -n https://src.fedoraproject.org/rpms/xarchiver.git /var/lib/mock/f45-build-38602-725/root/chroot_tmpdir/scmroot/xarchiver
Cloning into '/var/lib/mock/f45-build-38602-725/root/chroot_tmpdir/scmroot/xarchiver'...
$ git fetch origin 545c84d4f210964e63bddaeb25dd2a5102a0a4a3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xarchiver
 * [new ref]         545c84d4f210964e63bddaeb25dd2a5102a0a4a3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 545c84d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild