> Two other good cases in point (including specific error numbers
> mentioned down the thread) are ShellCheck and Rust.

Thanks. Good stuff.

> ShellCheck has an online database with examples of errors and fixes,
> rationale, etc.:
>
> [...]
>
> I personally would rather prefer to be offline-first and avoid putting
> details behind an URL, like rustc's --explain option:

Good idea. We could place the error catalog as S-expression metadata and
text files under https://github.com/schemedoc. Then generate the subsite
under Scheme.org from that metadata.