$ git clone -n https://github.com/xcp-ng-rpms/xcp-ng-release.git /var/lib/mock/v8.3-incoming-10213-28716/root/chroot_tmpdir/scmroot/xcp-ng-release
Cloning into '/var/lib/mock/v8.3-incoming-10213-28716/root/chroot_tmpdir/scmroot/xcp-ng-release'...
$ git fetch origin 9dcbea3a725f4ed048591558b467169d6df60712:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-ng-release
 * [new ref]         9dcbea3a725f4ed048591558b467169d6df60712 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9dcbea3 Merge pull request #41 from xcp-ng-rpms/XCPNG-2787/master