Punctuation characters in Debian packaging

[Ian Jackson <ijackson@chiark.greenend.org.uk>]

I have just made this wiki page:
  https://wiki.debian.org/Punctuation

There are probably a lot of things missing.  If you know about some
corner of Debian tooling which has exciting syntax, please add the
information you have.

I have deliberately not listed use in regexps, because regexp engines
have a quoting mechanism, and because I didn't want this to become a
table of regexp syntax.

I'm interested in things which appear in conventional filenames,
RFC822-syntax metadata (in source and binary packages, etc.), apt and
dpkg command lines, etc.

It would be nice if the statement at the bottom

  Other than as noted above, punctuation characters are not permitted
  in package names and version numbers.

could be extended to architectures, suites and filenames.  Since
architectures, suites and filename extensions are pretty much closed
sets, it would be best if those responsible for assigning them
documented what their actual rule is (which might differ from that
documented in some code somewhere).

Ian.