$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-10296-28865/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-10296-28865/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin ff5ce6a696793131ca24779980a6511e9dbdcb24:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         ff5ce6a696793131ca24779980a6511e9dbdcb24 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ff5ce6a bump release for test build