An user.js is a configuration file that can control Thunderbird settings - for a more technical breakdown and explanation, you can read more in the wiki.

🟩 Thunderbird user.js

The thunderbird user.js is a template which aims to provide as much privacy and enhanced security as possible, and to reduce tracking and fingerprinting as much as possible - while minimizing any loss of functionality and breakage (but it will happen).

Everyone, experts included, should at least read the wiki, as it contains important information regarding a few user.js settings.

It differs from the arkenfox user.js in that the focus is to keep Thunderbird as an e-mail client and disable as many web browsing features as possible. We believe web browsing should be done in a web browser, and not an email client.

If you're using Thunderbird (< 68) with Tor we suggest that you install the TorBirdy add-on. If you are using Tor, you should also consider using Tails or Whonix.
If you're using Gmail, please check this article about OAuth2.
For information about extensions, see the Wiki.
Calendar users should see this page.

Also be aware that this user.js is made specifically for Thunderbird and is only being tested against releases with extended support (ESR).

🟧 Sitemap

🟥 Acknowledgments

@tya99 most of the ground work and initial port from the Firefox version of arkenfox user.js
@dngray continual maintenance and Wiki
@HorlogeSkynet continual maintenance

README.md

Thunderbird User.JS

🟪 user.js