Webextension-Starter – Write Once Run on Any Browser Extension Starter

Any browser except Safari.

Currently I really enjoy Safari and it's extension model. Each extension has an app, so you can usually find them on the App Store, use them independently of Safari and change settings and things with a native UI. Example: OTP Auth--an app to store 2-factor authentication tokens. Started on iPhone but now it has an app, menu icon, browser extension and so on. All with 1 download (on desktop, and another on mobile).