$ git clone -n https://github.com/xcp-ng-rpms/xcp-ng-release.git /var/lib/mock/v8.3-u-gln1-10965-29416/root/chroot_tmpdir/scmroot/xcp-ng-release
Cloning into '/var/lib/mock/v8.3-u-gln1-10965-29416/root/chroot_tmpdir/scmroot/xcp-ng-release'...
$ git fetch origin 91a3f3f75f8ac81358aa9c10e6af3b07c3ec4327:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-ng-release
 * [new ref]         91a3f3f75f8ac81358aa9c10e6af3b07c3ec4327 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 91a3f3f bump release for test build