I expect you're remembering User:Lupin/popups.js[1], which dates back to August 2005. It soon became known as Navigation Popups[2], and is still available toda

I expect you're remembering User:Lupin/popups.js[1], which dates back to August 2005. It soon became known as Navigation Popups[2], and is still available today. The main documentation for Page Previews mentions Navigation Popups.[3] [1]: https://en.wikipedia.org/wiki/User:Lupin/popups.js https://en.wikipedia.org/wiki/User:Lupin/popups.js [2]: https://en.wikipedia.org/wiki/Wikipedia:Tools/Navigation_popups https://en.wikipedia.org/wiki/Wikipedia:Tools/Navigation_pop... [3]: https://www.mediawiki.org/wiki/Page_Previews https://www.mediawiki.org/wiki/Page_Previews