$ git clone -n https://github.com/xcp-ng-rpms/xen.git /var/lib/mock/v8.2-u-tescande1-8883-27838/root/chroot_tmpdir/scmroot/xen
Cloning into '/var/lib/mock/v8.2-u-tescande1-8883-27838/root/chroot_tmpdir/scmroot/xen'...
$ git fetch origin 5cb0580d56f01506d6204264c8f7baa9fa1b0d46:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xen
 * [new ref]         5cb0580d56f01506d6204264c8f7baa9fa1b0d46 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5cb0580 bump release for test build