MPL Beta 2 released- please continue informal review

Luis Villa luis at
Tue Mar 29 18:41:55 UTC 2011

On Tue, Mar 29, 2011 at 10:54 AM, John Cowan <cowan at> wrote:
> Luis Villa scripsit:
>> Specifically, in this Beta, GPL compatibility changes from opt-in to
>> opt-out; in other words, the default is that MPL is now GPL compatible
>> by its own terms (as discussed with Larry last time around, certain
>> interpretations of GPL may mean that MPL is always GPL compatible
>> regardless of this language; we do not intend for this language to
>> change that situation.)
> I think that's fine.
> What's not clear to me is what exactly the rights of a Larger Work author
> are.  If I want to incorporate Compatible Software into a GPL Larger Work,
> I make a GPL-only copy of the Compatible Software under 11.3 and then I
> can do it.

Assuming You are the party who combines the MPL work with the GPL
work, You can't directly make a GPL-only copy; you must "make sure the
requirements of this License are fulfilled
for the Covered Software"- i.e., You must effectively dual-license.
Someone who gets it from You can then use it under GPL-only terms if
they'd like, though.

> Can I instead dual-license the Larger Work under MPL+GPL,
> assuming there are no other GPL-only components?

There must be a GPL-only component, since you must "combin[e] the
Covered Software with a work governed by a Secondary License."

Sorry if this is confusing; I'm not trying to be deliberately obtuse;
this language is, as far as we know, different from how any other
license does this, and so a bit hard to understand, though we hope
better in B1 than B2.

Tangentially, we are now aware of another license with a similar
approach- limit the initial licensee, but allow different licensing
for people who receive from the initial licensee- which is in the
planning stages, though I don't know if those authors were aware of
our work when they started on that project.


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