Even though MediaWiki does know the proper date/time format for every language (and allows the user to select his/her preferred), it uses these for outputting timestamps on e.g. history pages (or formatting the ~~~~ signatures). But I don’t think there is a magic word / parser function / something which would provide this information into wikitext? (Yeah, the user-configured option cannot be sent to the parser, as it would break caching, but at least the default format for the content language? I guess not.)

Indeed, that’s would be a nice feature. There is T223772 which requests it.

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Pols12