Launched in June 2010, the HTTPS Everywhere browser extension is one of the most successful browser extensions ever released. The extension worked by automatically switching web connections from HTTP to HTTPS if websites had an HTTPS option available. At the time it was released, it helped upgrade site connections to HTTPS when users clicked on HTTP links or typed domains in their browser without specifying the "https://" prefix. The extension reached cult status among privacy advocates and was integrated into the Tor Browser and, after that, in many other privacy-conscious browsers. But since 2010, HTTPS is not a fringe technology anymore. Currently, around 86.6% of all internet sites support HTTPS connections. Browser makers such as Chrome and Mozilla previously reported that HTTPS traffic usually accounts for 90% to 95% of their daily connections.
From EFF's announcement: The goal of HTTPS Everywhere was always to become redundant. That would mean we'd achieved our larger goal: a world where HTTPS is so broadly available and accessible that users no longer need an extra browser extension to get it. Now that world is closer than ever, with mainstream browsers offering native support for an HTTPS-only mode.
With these simple settings available, EFF is preparing to deprecate the HTTPS Everywhere web extension as we look to new frontiers of secure protocols like SSL/TLS... We know many different kinds of users have this tool installed, and want to give our partners and users the needed time to transition.
The announcement also promises to inform users of browser-native HTTPS-only options before the day when the extension reaches its final sunsetting — and ends with instructions for how to activate the native HTTPS-only features in Firefox, Chrome, Edge, and Safari, "and celebrate with us that HTTPS is truly everywhere for users."