&gt; To your concerns regarding stable APIs: that&#x27;s exactly what WebExtensions are designed to address: decoupling add-on APIs from implementation details so that we can keep add-ons working, even as we refactor Firefox to be faster, more stable, and more efficient.<p>Ok, that sounds nice, but is this yet another extension API that does it Chrome-style, restricting extensions to a solitary button in a solitary toolbar, rather than giving them the freedom to truly extend the browser and its UI?  Because if I wanted handicapped extension APIs, I&#x27;d just use Chrome.<p>And besides, isn&#x27;t that what Jetpack was supposed to be?  How long until the next extension API that will get it right This Time?<p>One of the foundational pillars of Firefox is its powerful extension API, however messy and difficult-to-refactor it may be.  Take that away, and it&#x27;s just another browser, no better than Chrome.