$ git clone -n https://github.com/xcp-ng-rpms/xcp-emu-manager.git /var/lib/mock/v8.3-incoming-9927-28628/root/chroot_tmpdir/scmroot/xcp-emu-manager
Cloning into '/var/lib/mock/v8.3-incoming-9927-28628/root/chroot_tmpdir/scmroot/xcp-emu-manager'...
$ git fetch origin 48c055d51720c4e126135af973a7a6de3df91adf:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/xcp-emu-manager
 * [new ref]         48c055d51720c4e126135af973a7a6de3df91adf -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 48c055d updated spec + new source