I would find it helpful to understand the motivation for direct references as
defined in PEP 440, and some clarifications of how they can be used. For
* Can they be used together with other clauses? As PEP 440 appears now, it
seems to indicate that they can, but what does it mean in practice to have a
clause which is so specific with other clauses which are less specific?
* Can we have information in the "Direct reference" section summarising where
such references can and can't appear?
* What direct references provide which cannot be provided by the other version
clauses together with (separately) URIs or paths for where archives can be
found? The fact that the format of this clause is so different from all the
others suggests that it doesn't really belong with them.
There are also questions on other areas:
* It would appear that explicit prefix matching only makes sense for == and !=
clauses (as it is implicit for e.g.<, > clauses). If so, can this be stated
* Since pre-/post-/dev- suffixes are ignored for the purposes of prefix
matching, and given that implicit prefix matching is used with ~= , < and >,
does this mean that explicit prefix matching is only useful for >=, <=?
(given that == with prefix matching appears equivalent to ~=)
It would also be useful to document what kinds of matches would not be possible
without ~= and explicit prefix matching (trailing .*), assuming we had implicit
prefix matching for ==/!= clauses.