$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-10218-28792/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-10218-28792/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 9e6c62475cd2cc53a3de3d8d159afd4461ed127e:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         9e6c62475cd2cc53a3de3d8d159afd4461ed127e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9e6c624 bump release for test build