$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-9004-27905/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-9004-27905/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 4d10516762d1499fab32968a2312868fb0ad7391:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         4d10516762d1499fab32968a2312868fb0ad7391 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4d10516 bump release for test build