$ git clone -n https://src.fedoraproject.org/rpms/xrootd.git /var/lib/mock/f40-build-2521589-61799/root/chroot_tmpdir/scmroot/xrootd
Cloning into '/var/lib/mock/f40-build-2521589-61799/root/chroot_tmpdir/scmroot/xrootd'...
$ git fetch origin e8cf9f15913294baa6be05d078c0d1a4787d684f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xrootd
 * [new ref]         e8cf9f15913294baa6be05d078c0d1a4787d684f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e8cf9f1 Update to version 5.6.8