Finally! WebExtensions (<a href="https://developer.mozilla.org/en-US/Add-ons/WebExtensions" rel="nofollow">https://developer.mozilla.org/en-US/Add-ons/WebExtensions</a>) have slowly been becoming an adhoc standard for a little while now, but with a few tricky small differences here and there between browsers (e.g. <a href="https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Chrome_incompatibilities" rel="nofollow">https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Ch...</a>). So far it's just been Firefox and Edge slowly building a close approximation of Chrome's existing API, but a proper standard for this would be great, and make it much clearer what extension developers can _depend_ on, and what's optional.<p>Right now you basically write your extension once (probably for Chrome), and then port it to the others, often with various small manual changes or workarounds for incompatibilities. It's much better than it used to be, but still pretty inconvenient and error prone.<p>I can see at least a couple of differences with current implementations though, like using the `browserext://` protocol instead of `moz-extension://` and `chrome-extension://`. Does anybody more involved with this have a summary of the differences between this spec and Firefox, Edge and Chrome's implementations?