$ git clone -n https://src.fedoraproject.org/rpms/grub2.git /var/lib/mock/f40-build-2386647-60496/root/chroot_tmpdir/scmroot/grub2
Cloning into '/var/lib/mock/f40-build-2386647-60496/root/chroot_tmpdir/scmroot/grub2'...
$ git fetch origin 29406ad33366ac899ae5035cf26589d82652bc9e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grub2
 * [new ref]         29406ad33366ac899ae5035cf26589d82652bc9e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 29406ad xfs: include directory extent parsing patch