free-soft Mozilla add-on

[Igor Zobin]

Hello,

I have found the Thunderbirdbiff add-on for both Firefox and 
Thunderbird, that is not listed as free-soft add-on on gnu.org. The 
add-on is released under the MPL 1.1.
Link to the project homepage: http://thunderbirdbiff.mozdev.org/
Here they state everything on that page is under MPL 1.1: 
http://www.mozdev.org/copyright.html

Have a nice day!