The clear standard is trailing "." after each numeric section. This fixes
the small handful of outliers. This makes it easy to convert these headers
to common markup formats, for example:
http://hyperpolyglot.org/lightweight-markup
the only exciting one is that we don't use guards to defend against
"enumeration attacks" -- i'm not quite sure what an enumeration attack
is, but it sounds like something where the guard is able to make a list
of users, and where having that list is bad news in itself. that's not
quite what guards are for.
