Display mailing list header is an extension that implements RFC 2369 for SeaMonkey: Special mailing list header fields in the mail are parsed, and the links are displayed in the extended header view. You can click them to simply go to the archive, request help or unsubscribe from the list.
You have to install Enigmail OR Mnenhy, as this extension relies on getting special headers from the mail which is very complicated to achieve in current versions of thunderbird.
How to Install in Thunderbird:
1. Right-click the link below and choose "Save Link As..." to download and save the file to your hard disk.
2. In Mozilla Thunderbird, open Add-ons from the Tools menu.
3. Click the Install button, and locate/select the file you downloaded and click "OK".
· Mozilla Thunderbird