The Cargo extension (https://www.mediawiki.org/wiki/Extension:Cargo) defines a page, Special:ViewData, that serves two purposes: (1) to display additional query results when a user clicks on "More results" from within a main set of query results; and (2) to provide a user interface - if a user goes directly there - to run any Cargo query. For this 2nd use, the interface could be improved quite a bit: right now the UI is just some text inputs, with no autocompletion, no validation, no additional, format-based inputs, and in general no help to the user. It would be great to have a much more user-friendly interface, using autocompletion, dropdowns, and/or other form elements, so that users didn't have to, for example, guess what tables and fields exist on the wiki. It could be helpful to look at existing interfaces that do similar things - like Semantic MediaWiki's Special:Ask page, or the phpMyAdmin interface - for inspiration.
It probably also makes sense to rename Special:ViewData to Special:CargoQuery at the same time - I don't really like the name Special:ViewData any more.
Mentors: Yaron Koren, Nikhil Kumar