Thread:Extension talk:TemplateData/Status of this api/reply

The extension is installed on all public Wikimedia wikis (but yes, we need to document the API). However, it relies on templates having data written about them by hand, which is not yet done except for a very small number of demonstration templates. We're going to recommend that people start writing these very soon, but it may take some time, depending on how popular and well-maintained the templates you're interested in are.