$ git clone -n https://src.fedoraproject.org/rpms/libpng12.git /var/lib/mock/f41-build-832216-14881/root/chroot_tmpdir/scmroot/libpng12
Cloning into '/var/lib/mock/f41-build-832216-14881/root/chroot_tmpdir/scmroot/libpng12'...
$ git fetch origin 7680d05824749acc31ee9079cd37c70834191aca:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libpng12
 * [new ref]         7680d05824749acc31ee9079cd37c70834191aca -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7680d05 Eliminate use of obsolete %patchN syntax (#2283636)