This is the superior userscript manager. It's free & open source, it works perfectly, and has frequent updates. Goodbye tampermonkey, rip Greasemonkey (hasn't worked right in years).
A great, modern alternative to Greasemonkey, also in terms of the supported API. And it's open source (unlike Tampermonkey), which I consider pretty important for an extension that can access and modify every page you visit!
