MediaWiki:3
`:3` isn't a valid page title in #MediaWiki though unfortunately
Lucas Werkmeister@mediawiki it’s a valid way to link to [[3]] though
@LucasWerkmeister totally didn't check that you can't use `:3` as a title on test.wiki before posting this ^^"
--Sammy
@mediawiki also some wikis may or may not mess with the displayed title :3 https://en.wiktionary.org/wiki/Unsupported_titles/:3
C.Suthorn 
In German language the colon (:) is used as a gender marker: Autor:in.
It is possible to use the colon in wiki page titles: ...wikimedia.org/wiki/Autor:in
However there is one exception: the colon is forbidden in filenames of files on commons, if the file or a revision thereof has been uploaded after 2019. There are still hundreds of older files that have a colon, and cannot be updated. And there is this file:
Betriebszentrale_S-Bahn_Berlin,_Halenseestraße_am_Friedhof_Grunewald_mit_Stellenanzeige_Fahrdienstleiter:in_am_2023-05-17.png
MediaWiki forcibly un-genders the name.
taco, bird/cat 
@LucasWerkmeister @mediawiki just had to point out that :3c is a synonym for :3 and that honestly made my week
#Guigui 🇫🇷@mediawiki literally 1984 😔
Essem 
@mediawiki literally unusable
Meow@mediawiki Back in the UseModWiki era, a page titled " " (one space) was valid.