Firefox 54: E10S-Multi, WebExtension APIs, CSS clip-path

https://hacks.mozilla.org/2017/06/firefox-54-e10s-webextension-apis-css-clip-path/

Today’s release completes Firefox’s transformation into a fully multi-process browser, running many simultaneous content processes in addition to a UI process and, on Windows, a special GPU process. 

It also improves stability, ensuring that a single content process crashing won’t take out all of your other tabs, nor the rest of the browser.
Firefox continues its rapid implementation of new WebExtension APIs. 

For example, the screenshot below shows the Chrome version of the Vue.js DevTools running in Firefox without any modifications.

The CSS clip-path property allows authors to define which parts of an element are visible. 

https://www.mozilla.org/en-US/firefox/54.0/releasenotes/