$ git clone -n https://github.com/xcp-ng-rpms/xapi.git /var/lib/mock/v8.3-u-gtn1-9516-28254/root/chroot_tmpdir/scmroot/xapi
Cloning into '/var/lib/mock/v8.3-u-gtn1-9516-28254/root/chroot_tmpdir/scmroot/xapi'...
$ git fetch origin 58281f6e6522426aeeab4e8f6eaee6f2e4e69126:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xapi
 * [new ref]         58281f6e6522426aeeab4e8f6eaee6f2e4e69126 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 58281f6 bump release for test build