I’ve just discovered the MoreColsForAddressBook extension for Thunderbird.
It’s not obvious from its name, but it provides import/export tools and additional entries for contacts in your Mozilla address book, which includes really useful operations that support vCard! This makes a great companion for those of us who use the vCard format to share our contact details with the world.
The extension doesn’t appear to be listed in Mozilla’s add-on repository, so I thought it was worth giving this an airing here. Read more about this extension on its page: MoreColsForAddressBook