$ git clone -n https://src.fedoraproject.org/rpms/grub2-breeze-theme.git /var/lib/mock/f42-build-3426781-45197/root/chroot_tmpdir/scmroot/grub2-breeze-theme
Cloning into '/var/lib/mock/f42-build-3426781-45197/root/chroot_tmpdir/scmroot/grub2-breeze-theme'...
$ git fetch origin be77a6cc9da0de7bf991d931460e37dcd01d6a0d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grub2-breeze-theme
 * [new ref]         be77a6cc9da0de7bf991d931460e37dcd01d6a0d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be77a6c 6.3.3