$ git clone -n https://github.com/xcp-ng-rpms/mellanox-mlnxen.git /var/lib/mock/v8.3-incoming-8925-27873/root/chroot_tmpdir/scmroot/mellanox-mlnxen
Cloning into '/var/lib/mock/v8.3-incoming-8925-27873/root/chroot_tmpdir/scmroot/mellanox-mlnxen'...
$ git fetch origin a2700613a9ba97e2982d9f742d6ce11e897dbb5c:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/mellanox-mlnxen
 * [new ref]         a2700613a9ba97e2982d9f742d6ce11e897dbb5c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a270061 Merge branch 'XS-8.3' into 8.3-import_mellanox-mlnxen-5.9_0.5.5.0-3.xs8.src.rpm