$ git clone -n https://github.com/xcp-ng-rpms/xcp-ng-release.git /var/lib/mock/v8.3-u-gln1-10810-29324/root/chroot_tmpdir/scmroot/xcp-ng-release
Cloning into '/var/lib/mock/v8.3-u-gln1-10810-29324/root/chroot_tmpdir/scmroot/xcp-ng-release'...
$ git fetch origin 5987067d631a6ac95ffc0f2fb701fd6a8d258267:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-ng-release
 * [new ref]         5987067d631a6ac95ffc0f2fb701fd6a8d258267 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5987067 bump release for test build