Amir E. Aharoni, 09/10/2014 20:21:
The question of date formats came up on the India
mailing list [1] and
this made me think: Currently, how does a MediaWiki instance decide what
is its default date format? CLDR, PHP or something internal?
Internal.
See
https://www.mediawiki.org/wiki/Localisation#What_can_be_localised
Nemo