$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn2-9226-28013/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn2-9226-28013/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 4a41cd62baae79c6a231173a86b6411001e8d9da:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         4a41cd62baae79c6a231173a86b6411001e8d9da -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4a41cd6 bump release for test build