> file contents should ideally be self-describing. `#!r6rs`
> and `#! /usr/bin/env fantastic-scheme` are two such useful identifiers.
> Perhaps the  `meta.scm` file can start with `#!metadata` or something.
> Would that be considered reader abuse?
Come to think of it, since Scheme has a separate metalevel for
`define-library`, how come there isn't a general `#!meta` read flag?
That would obviate the need for the separate `.sld` filename extension
as well.

Maybe it's because the separate metalevel is not a required part of
R7RS, but just one implementation strategy?

In any case, that reader flag could potentially be useful. This corner
of Scheme is a bit murky to me, so it's possible I'm missing an obvious
reason why it's a bad idea.

If there's a `meta.scm` or `scheme.scm` library lookup metadata file,
perhaps that file should have yet another reader flag.

There could be a general `#!data` flag for files that are not Scheme
program or library definitions.