$ git clone -n https://github.com/xcp-ng-rpms/varstored.git /var/lib/mock/v8.3-incoming-10689-29239/root/chroot_tmpdir/scmroot/varstored
Cloning into '/var/lib/mock/v8.3-incoming-10689-29239/root/chroot_tmpdir/scmroot/varstored'...
$ git fetch origin e9cb6f1d5dcbfad3468e53a7b9dea523f3e9bcd9:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/varstored
 * [new ref]         e9cb6f1d5dcbfad3468e53a7b9dea523f3e9bcd9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e9cb6f1 Merge branch 'XS-8.3'