$ git clone -n https://github.com/xcp-ng-rpms/sm.git /var/lib/mock/v8.3-incoming-9355-28113/root/chroot_tmpdir/scmroot/sm
Cloning into '/var/lib/mock/v8.3-incoming-9355-28113/root/chroot_tmpdir/scmroot/sm'...
$ git fetch origin 21c0e8b86f56fa6bcb0d8dce672cccbb72aa5ad8:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/sm
 * [new ref]         21c0e8b86f56fa6bcb0d8dce672cccbb72aa5ad8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 21c0e8b Merge pull request #84 from xcp-ng-rpms/8.3-update-3.2.12-10