Cross-wiki Search Result Improvements/explore similar

What?

 * Upon arriving at the search result page after querying Wikipedia, additional information will be displayed containing related article page links, categories, and languages that the article can also be read in.

Where?

 * The links will be visible by moving the users cursor over each search result returned. There will be 3 new links for: related articles, categories and languages that can be hovered over to display their contents.

How?

 * Logged in users can test this new functionality by editing (or creating) a common.js file - more information can be found in the self-guided testing page.

Why?

 * We want to find out if adding related information to the search results will aid users with additional rich data that is useful in the context of the search query the user inputted.

Can I help?

 * Yes, please!
 * Update your common.js file in your logged-in profile and try out the functionality and let us know what you think of the results. Are they interesting and/or useful; do they help with your research or editing needs; do they pique your curiosity about information related to your original search query? Feel free to add questions and constructive comments in the talk page.

Additional outreach

 * We've identified a few communities that might be interested in providing early feedback for this new functionality:
 * * English Wikipedia help-talk:searching
 * * English Wikipedia request a query
 * * English Wikipedia help desk
 * * Wikitech Ambassadors list
 * * French Wikipedia Village Pump

Hasn't something like this been done before?

 * Yes, there was a similar extension that was created as part of a new project for related pages that was introduced in the mobile apps and as a beta feature on desktop and mobile web.
 * Initial community feedback was to: not appear for disambiguation pages and only use non-free images in certain circumstances. This is the current phabricator ticket for related pages on mobile.