$ git clone -n https://src.fedoraproject.org/rpms/repo.git /var/lib/mock/f39-build-1649688-40472/root/chroot_tmpdir/scmroot/repo
Cloning into '/var/lib/mock/f39-build-1649688-40472/root/chroot_tmpdir/scmroot/repo'...
$ git fetch origin 845fd65721e5765ca92cc4c81ffa63d9b488d115:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/repo
 * [new ref]         845fd65721e5765ca92cc4c81ffa63d9b488d115 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 845fd65 Update to 2.35