$ git clone -n https://src.fedoraproject.org/rpms/grilo.git /var/lib/mock/f42-flatpak-app-build-59164066-6571399/root/chroot_tmpdir/scmroot/grilo
Cloning into '/var/lib/mock/f42-flatpak-app-build-59164066-6571399/root/chroot_tmpdir/scmroot/grilo'...
$ git fetch origin 5c457265a33b2d87c825ed4cd3fc027afc62816c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grilo
 * [new ref]         5c457265a33b2d87c825ed4cd3fc027afc62816c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5c45726 Fixed possible regressions from GTask port