The Cite extension implements an API `action=query&prop=references`[1], which was written to support a reference lazy-loading feature for mobile clients but never used. This was a beta feature and the API was never enabled on Wikimedia sites.[2] If you query it, you'll see nothing but an error response.

My team is currently refactoring the Cite extension, and we would prefer to remove the API rather than continue maintaining dead code. Please respond by the end of the week if you know of any non-Wikimedia sites where the API is enabled and in use, otherwise we'll continue with the plan to remove it without a deprecation period.

Thank you, Adam

[1] https://en.wikipedia.org/w/api.php?action=help&modules=query%2Breference... [2] https://phabricator.wikimedia.org/T222373