$ git clone -n https://github.com/xcp-ng-rpms/xen.git /var/lib/mock/v9.0-u-ydi1-11147-29553/root/chroot_tmpdir/scmroot/xen
Cloning into '/var/lib/mock/v9.0-u-ydi1-11147-29553/root/chroot_tmpdir/scmroot/xen'...
$ git fetch origin 0744c16ee470a9cc8bff37a06dc116da5aebd2c5:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xen
 * [new ref]         0744c16ee470a9cc8bff37a06dc116da5aebd2c5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0744c16 bump release for test build