$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-10316-28885/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-10316-28885/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 65f36a7a242411ed14a0e53905d21f165fa5a9c0:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         65f36a7a242411ed14a0e53905d21f165fa5a9c0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 65f36a7 bump release for test build