$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-9865-28585/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-9865-28585/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 787d049dc489f12a76a4043cec1f63ae1c0202be:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         787d049dc489f12a76a4043cec1f63ae1c0202be -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 787d049 bump release for test build