To try the thousands of add-ons available here, download Mozilla Firefox, a fast, free way to surf the Web!
CloseWelcome to Firefox Add-ons.
Choose from thousands of extra features and styles to make Firefox your own.
CloseReview for User Agent Switcher by miitwo
Rated 5 out of 5 stars
I've been using this for a long time and hope it will be ported to webextension some day. Currently does not support multiprocess, but still a great add-on.
To create your own collections, you must have a Mozilla Add-ons account.