$ git clone -n https://src.fedoraproject.org/rpms/libpng.git /var/lib/mock/f41-build-729163-13151/root/chroot_tmpdir/scmroot/libpng
Cloning into '/var/lib/mock/f41-build-729163-13151/root/chroot_tmpdir/scmroot/libpng'...
$ git fetch origin beb4b221ac8480004dc338604742d32df4553e87:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libpng
 * [new ref]         beb4b221ac8480004dc338604742d32df4553e87 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at beb4b22 Eliminate use of obsolete %patchN syntax (#2283636)