$ git clone -n https://github.com/xcp-ng-rpms/xcp-ng-release.git /var/lib/mock/v8.3-u-pcoval2-10164-28753/root/chroot_tmpdir/scmroot/xcp-ng-release
Cloning into '/var/lib/mock/v8.3-u-pcoval2-10164-28753/root/chroot_tmpdir/scmroot/xcp-ng-release'...
$ git fetch origin d71dbd80d03e7666a6ed36d02e3c754436080d59:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-ng-release
 * [new ref]         d71dbd80d03e7666a6ed36d02e3c754436080d59 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d71dbd8 bump release for test build