Vanilla JS has also been a long-time joke about how modern javascript has advanced far enough not to need libraries for a lot of stuff people still reach for: http://vanilla-js.com/

Goes back to 2012 unchanged (hence the selection of libraries compared against): https://web.archive.org/web/20120825232614/http://vanilla-js...

Edit to add: Having been around in that era, I see "Vanilla Prime" as a whole new framework, nothing vanilla about it.