$ git clone -n https://github.com/xcp-ng-rpms/xcp-ng-release /var/lib/mock/v8.3-incoming-9721-28430/root/chroot_tmpdir/scmroot/xcp-ng-release
Cloning into '/var/lib/mock/v8.3-incoming-9721-28430/root/chroot_tmpdir/scmroot/xcp-ng-release'...
$ git fetch origin 8d5455777d93ec3a26ab1bfcbf65443318d37f4b:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-ng-release
 * [new ref]         8d5455777d93ec3a26ab1bfcbf65443318d37f4b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8d54557 Merge pull request #37 from xcp-ng-rpms/pcl/review/master