[Note that the following is not an official mozilla.org statement; a lot of it is simply my personal opinion.]
Christopher S. Charabaruk wrote: > If you saw the cancelled message, please ignore it in favor of this one. > > I saw MPL on that page, and stopped after that. I didn't see NPL (until > a later reading of the page). However, RMS also says not to use the MPL. Yes, but this has nothing to do with whether RMS considers the MPL is a free software license or not. (And in fact RMS does consider the MPL, along with the NPL, to be a free software license fulfilling the criteria set forth in the FSF document "What is Free Software". That's why the NPL and MPL are included in the FSF's free software license list.) RMS and the FSF do not recommend use of the MPL by software developers who are creating new software and who are deciding what license they should use when distributing that software. This is natural enough -- RMS and the FSF want to promote the use of the GPL as the only free software license that people should use. The MPL, like the GPL, is a copyleft license, i.e., it explicitly requires that (some subset of) derivative works be distributed under the same license terms as was the original code. However the MPL has a weaker form of copyleft than the GPL, since the MPL explicitly exempts from the copyleft requirement new source files that are not based on the original (MPL-licensed) source files. RMS and the FSF would like copyleft provisions to be as strong as possible, so as to ensure that (as much as possible) all software based on free software is itself free software; this minimizes the possibility that people might take the source code for free software products and use that code in creating non-free (proprietary) products. Thus RMS and the FSF are motivated to discourage all licenses with weaker copyleft provisions than the GPL; in particular, they discourage use of the MPL, NPL, LGPL, and other non-GPL copyleft licenses. One major way in which RMS and the FSF discourage the use of non-GPL copyleft licenses is to declare that they are in some way "incompatible" with the GPL. Whether this is true or not is an open question; no court has ever rendered an opinion on this. If you want an "official" opinion, go ask a lawyer. However regardless of whether the MPL, NPL, etc., are "really" incompatible with the GPL or not, certainly RMS and the FSF have sufficient motivation (IMO) to claim that they are -- I would not expect them to do otherwise. (To my knowledge the LGPL is the only non-GPL copyleft license that RMS and the FSF consider to be compatible with the GPL. This probably has to do with the facts that a) RMS and the FSF wrote both the GPL and LGPL; and b) the LGPL has a provision explicitly allowing people to convert LGPL-ed code over to the GPL.) This is the key reason why we initiated the project to relicense the Mozilla code: so that people who agreed with RMS and the FSF could have the option of using Mozilla code under GPL terms instead of NPL or MPL terms. (We added the option of using the Mozilla code under LGPL terms as well; unlike RMS and the FSF, we have no inherent interest in discouraging use of the LGPL, and we were concerned that allowing only the GPL as an alternate license might cause problems in some cases for people using the LGPL for their own code.) But the bottom line is this: No matter which license option you elect to use (NPL/MPL, GPL, or LGPL), IMO the Mozilla code as distributed by mozilla.org is free software according to the criteria put forth by RMS and the FSF. Frank -- Frank Hecker [EMAIL PROTECTED]
