{ "webextensions": { "manifest": { "chrome_url_overrides": { "__compat": { "mdn_url": "https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/manifest.json/chrome_url_overrides", "support": { "chrome": { "version_added": true }, "edge": { "version_added": "79" }, "firefox": { "version_added": "54" }, "firefox_android": { "version_added": false }, "opera": { "version_added": false }, "safari": { "version_added": false } } }, "bookmarks": { "__compat": { "support": { "chrome": { "version_added": true }, "edge": { "version_added": "79" }, "firefox": { "version_added": false }, "firefox_android": { "version_added": false }, "opera": { "version_added": false }, "safari": { "version_added": false } } } }, "history": { "__compat": { "support": { "chrome": { "version_added": true }, "edge": { "version_added": "79" }, "firefox": { "version_added": false }, "firefox_android": { "version_added": false }, "opera": { "version_added": false }, "safari": { "version_added": false } } } }, "newtab": { "__compat": { "support": { "chrome": { "version_added": true, "notes": "If two or more extensions both define a custom new tab page, then in Firefox the first extension to run wins. In Chrome the last extension wins." }, "edge": { "version_added": "79", "notes": "If two or more extensions both define a custom new tab page, then in Firefox the first extension to run wins. In Edge the last extension wins." }, "firefox": { "version_added": "54", "notes": "If two or more extensions both define a custom new tab page, then in Firefox the first extension to run wins. In Chrome the last extension wins." }, "firefox_android": { "version_added": false }, "opera": { "version_added": false }, "safari": { "version_added": false } } } } } } } }