
Such changes have their detractors, including, we dare say, the authors of the tens of thousands of addons that were broken by this change. XUL (and XPCOM, Mozilla’s bridge between C++ and JavaScript) gave a vibrancy to the Firefox add-on ecosystem, but given the security implications it was axed in favour of the new WebExtensions mechanism. The XUL architecture was powerful, perhaps too powerful since it enabled add-ons to do pretty much anything they wanted, including to other add-ons, the browser core or even the underlying operating system. Firefox 57 (Quantum) brought a new look, a newly engineered browser engine and a new add-on architecture to replace the venerable XUL (XML User Interface Language). NPAPI plugins were all but banished in 2017 when Firefox 52 was released.


Firefox has changed a lot over the past few years. Firefox also lost some of its popularity because of changes to the browser.
