jQuery 3.0 removed old IEInternet Explorer — Microsoft's browser that dominated the web in the 1990s and 2000s. hacks, improved animation performance, and tightened edge-case behavior — the line that assumed evergreen browsers only. WordPressA PHP CMS powering millions of sites — themes, plugins, and the block editor for publishing. and legacy themes eventually migrated; greenfield projects increasingly chose ReactA JavaScript library for building UIs — component trees and declarative rendering for the web. and Vue instead.

jQuery 3.0 drew a line under the IE6–8 era for the world's most-used JS library.

It signaled jQuery's shift from growth to maintenance as SPAs took over.