Although apparently not available in this moment, Firefox 67 is scheduled to arrive today all over the world. The new release of Mozilla's browser comes with private browsing mode extension controls, WebRender enabled for 5 percent of compatible systems, as well as various performance improvements and fixes.
https://www.notebookcheck.net/Firefox-67-0-rolls-out-with-WebRender-performance-improvements-and-more.421246.0.html
Nice! I use it and really like this browser.
Today I've got my update to Firefox 67 so yeah we can say it's available right now but not everyone is going to get it immediately.
I got it a few hours after publishing this article. I guess it already reached all corners of the world.