To clarify; the pywikipedia bug was caused by calling .strip() on the page title. When working with Unicode < 4.0, this will strip the U+200B character (python < 2.7), with Unicode > 4.0, this will *not* strip the U+200B character (python >= 2.7).

I don't _think_ it should be legit to have this char at beginning/end of a title, as zero-width space is meant to be used as a separator to disable ligatures etc, and only makes sense within a span of non-whitespace characters.

In the middle of words, it may actually be required for some languages.

Correct behavior is _probably_ to strip this char from beginning/end during title normalization, while preserving it in the middle of words. Once that's done, a run of cleanupTitle & co should pretty transparently correct existing titles.

I would recommend double-checking the definitions and actual usage to make sure these assumptions are correct before changing rules, however.

A user reported the existence of these two pages on Portuguese Wikipedia:
https://pt.wikipedia.org/wiki/Coming_Out_of_the_Dark
https://pt.wikipedia.org/wiki/Coming_Out_%E2%80%8B%E2%80%8Bof_the_Dark
which appear on lists such as
https://pt.wikipedia.org/wiki/Special:PrefixIndex/Coming_Out?uselang=en
as if they were two identically named pages.

Fortunatelly, this seems to be the only title where this character was used (at least on ptwiki):
http://tools.wmflabs.org/addshore/grep/?pattern=%E2%80%8B%E2%80%8B&lang=pt&wiki=wiki&ns=0

Just had a U+200B in a filename on my third party wiki, and I'd like to prevent that in the future, because it caused a bit of confusion and does not seem to serve any purpose.

But since this seems to be one of those endless-saga-bugs that never get addressed, is there an easy way for me as server-admin of said third party wiki to exclude this (and other) invisible character from filenames (pagenames too)?

edit: To answer my own question - apparently this is addressed by the Title-Blacklist on Wikipedia:

https://en.wikipedia.org/wiki/MediaWiki:Titleblacklist

specifically the line

.*[\x{00A0}\x{1680}\x{180E}\x{2000}-\x{200B}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}].*