Google, Microsoft, Apple, and Mozilla have launched the WebExtensions Community Group (WECG) The four organizations want to develop what amounts to web standards for browser extensions. The WECG’s efforts will not be focused on specifying, standardizing, or coordinating extension signing or delivery as these goals are out-of-scope according to the group’s charter. Every browser vendor will continue to operate their own fully independent extension stores, with separate technical, review, and editorial policies.
Source: https://www.bleepingcomputer.com/news/security/google-microsoft-and-mozilla-work-together-on-better-browser-extensions/