From translatewiki.net
This is the documentation subpage for the parent Template:Langcat page.
This template can be used to add the page to the relevant language category: it's appended to the category name and adds either nothing on the English page, or the language code on the translated pages; it needs the souce page title (without namespace) as parameter. Example for the Statistics page, to be included in a translatable page layout:
The template adds /en subpages to the /en categories to avoid double listing in the English (main) categories, although those categories will be mostly red links here on translatewiki.net.
This is an old legacy template: in most cases, newer translated pages should better use the newer parserfunction to determine the language suffix to return from the current translated page, without needing any parameter for the page to test for. It correctly generates the necessary suffix to be appended conditionally to the category name.