3e Calendar is a Thunderbird and SeaMonkey extension that enables 3e calendars support in the Lightning add-on.
3e Calendar is an open source add-on designed to work with Mozilla Thunderbird 10.0 or later and SeaMonkey 2.7 or later.
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".
Product's homepage
Requirements:
· Mozilla Thunderbird
· Lightning for Thunderbird