$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-9539-28284/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-9539-28284/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 291070957aab8eb6fa1f0ed2f5be5ff21e95048e:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         291070957aab8eb6fa1f0ed2f5be5ff21e95048e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2910709 bump release for test build