$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn2-9222-28013/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn2-9222-28013/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 3d953c6c01b8194d03461cd1aad217373506f558:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         3d953c6c01b8194d03461cd1aad217373506f558 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3d953c6 bump release for test build