$ git clone -n https://src.fedoraproject.org/rpms/retrace-server.git /var/lib/mock/f45-build-34492-687/root/chroot_tmpdir/scmroot/retrace-server
Cloning into '/var/lib/mock/f45-build-34492-687/root/chroot_tmpdir/scmroot/retrace-server'...
$ git fetch origin 3b8327222328d103d785eb0de73e0c3a445338e1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/retrace-server
 * [new ref]         3b8327222328d103d785eb0de73e0c3a445338e1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3b83272 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild