$ git clone -n https://src.fedoraproject.org/rpms/petsc.git /var/lib/mock/f42-build-864919-172651/root/chroot_tmpdir/scmroot/petsc
Cloning into '/var/lib/mock/f42-build-864919-172651/root/chroot_tmpdir/scmroot/petsc'...
$ git fetch origin 1b9b365abb7b434f79cff00d95b5159525d2a8d8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/petsc
 * [new ref]         1b9b365abb7b434f79cff00d95b5159525d2a8d8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1b9b365 Fix popd commands