Maybe make numerical file mode more readable
Right now the numerical file mode serializes to an integer and the meaning doesn't seem to obviously correspond to the traditional numerical unix modes. Probably we want something like r-wr-wr-w
to serialize as 555
or 0o555
or something rather than whatever number it currently serializes as.
Probably it's not worth a big performance hit just to accomplish this, though, since there's also a human-readable string right next to it.