$ git clone -n https://src.fedoraproject.org/rpms/grub2-breeze-theme.git /var/lib/mock/f40-build-2003292-44827/root/chroot_tmpdir/scmroot/grub2-breeze-theme
Cloning into '/var/lib/mock/f40-build-2003292-44827/root/chroot_tmpdir/scmroot/grub2-breeze-theme'...
$ git fetch origin 40c62d1a8851beb137a0fb1e75f9465e83ce14d8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grub2-breeze-theme
 * [new ref]         40c62d1a8851beb137a0fb1e75f9465e83ce14d8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 40c62d1 fix: upload missing sources