$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-incoming-11225-29598/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-11225-29598/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 4f9453ac51ba4dec983bfc9b2ea21eace07a571a:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         4f9453ac51ba4dec983bfc9b2ea21eace07a571a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4f9453a Merge branch 'XS-8.3' into asv/xsrebase-26.1.4