$ git clone -n https://github.com/xcp-ng-rpms/openssh.git /var/lib/mock/v8.3-incoming-10013-28660/root/chroot_tmpdir/scmroot/openssh
Cloning into '/var/lib/mock/v8.3-incoming-10013-28660/root/chroot_tmpdir/scmroot/openssh'...
$ git fetch origin e6498b61a231ca7dc64ff9f7118a1c3187fc0306:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/openssh
 * [new ref]         e6498b61a231ca7dc64ff9f7118a1c3187fc0306 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e6498b6 Merge branch 'XS-8.3'