$ git clone -n https://src.fedoraproject.org/rpms/grim.git /var/lib/mock/f45-build-13050-446/root/chroot_tmpdir/scmroot/grim
Cloning into '/var/lib/mock/f45-build-13050-446/root/chroot_tmpdir/scmroot/grim'...
$ git fetch origin 296119bbfaf610b680315909fff2eff4ef7fa92d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/grim
 * [new ref]         296119bbfaf610b680315909fff2eff4ef7fa92d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 296119b Convert to %autorelease and %autochangelog