$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-incoming-8870-27823/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-incoming-8870-27823/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 771b02b4976f8cff41160e351631a01b6209cf6b:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         771b02b4976f8cff41160e351631a01b6209cf6b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 771b02b Merge pull request #107 from xcp-ng-rpms/abo/xenopsd-amd-pci-bar-uc