$ git clone -n https://github.com/xcp-ng-rpms/xcp-ng-release.git /var/lib/mock/v8.3-incoming-10204-28716/root/chroot_tmpdir/scmroot/xcp-ng-release
Cloning into '/var/lib/mock/v8.3-incoming-10204-28716/root/chroot_tmpdir/scmroot/xcp-ng-release'...
$ git fetch origin 11fb9d3000e08f208579ab0f6351cbf57fd7db96:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-ng-release
 * [new ref]         11fb9d3000e08f208579ab0f6351cbf57fd7db96 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 11fb9d3 Preserve /etc/rsyslog.d/xenstore.conf if present