$ git clone -n https://src.fedoraproject.org/rpms/petsc.git /var/lib/mock/f41-build-851706-166118/root/chroot_tmpdir/scmroot/petsc
Cloning into '/var/lib/mock/f41-build-851706-166118/root/chroot_tmpdir/scmroot/petsc'...
$ git fetch origin 20acd58295a6d29e558a37e063e8b34dbfa1e407:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/petsc
 * [new ref]         20acd58295a6d29e558a37e063e8b34dbfa1e407 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 20acd58 Rebuild for mpich-4.1.2