Dennis Lee

These are the folders I save when backing up profiles for Thunderbird and Thunderbird-based email clients.

Extensions

The following 2 items are sufficient for fully restoring extensions.

extensions/
├── example@mozdev.org.xpi
├── {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}.xpi
└── [[:graph:]]+\.xpi

This folder stores extension files for all installed extensions (except ones which are pre-installed).

extensions.ini

List of enabled extensions. Human-readable format.

Authentication/logging in

The following 2 files must be combined with a proper prefs.js or user.js to fully restore logins.

key4.db

Server authentication credentials. If you delete this, you will be prompted to log in to your account(s) again the next time you open the program, but everything else will remain intact.

logins.json

Stores information about which accounts are currently logged in.

Mailbox storage

Mail/
└── Local Folders/

Folder for locally-stored mail.

ImapMail/
├── imap.example.com/
└── mail.example.net/

Folder for saving offline copies of mail which is synced with an IMAP server.

Settings storage

prefs.js

Stores all user preferences, including information about accounts. This file is edited by changing settings from within the graphical environment.

user.js

Can store any user preference, but values defined here will always take precedence over those stored in prefs.js when the program is started.