Hmmm I read that many times and I simply do not really understand the question. Thunderbird is an open source licensed project using the Mozilla license. To change the license to a closed source is actually rather difficult. Have a look at the license fact here https://www.mozilla.org/en-US/MPL/2.0/FAQ/ particularly Q11 The discussions pertaining to maintaining the free as in beer status of Thunderbird can be found in the archives of the Thunderbird planning mailing list of a number of years of discussions. https://thunderbird.topicbox.com/groups/planning If that is not what you are asking, it is my best understanding of that.