الإضافات

Synchronizes selected addressbooks with other instances of thunderbird
using local files, webdav servers or imap servers

Adds zoom and rotation functionality for images...

Implement the "Sensitivity" header for outgoing messages (described in RFC 4021 section 2.1.55).
This allows the user to select Private / Personal / Company-Confidential (or none) for an outgoing message.
No longer maintained: See below.