$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-9877-28593/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-9877-28593/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 6db72f9f158a4f4047751d6fc0fed2c8809213bb:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         6db72f9f158a4f4047751d6fc0fed2c8809213bb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6db72f9 bump release for test build