$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-9557-28304/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-9557-28304/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 06a1d43baaa14fefbe17be2877bd5bbef8fdc0f9:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         06a1d43baaa14fefbe17be2877bd5bbef8fdc0f9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 06a1d43 bump release for test build