Review for Thunderbird Message Filter Import/Export by tonyfirshman
Rated 1 out of 5 stars
Export is fine, buit no import, so useless.
As a Windows user said one can simply copy msgFilterRules.dat
For Apple this is:
Library -> Thunderbird -> Profiles -> <folder> -> imapMail <folder>/msgFilterRules.dat
To create your own collections, you must have a Mozilla Add-ons account.