This is the mozilla.org MPL FAQ. It aims to answer the most common questions
people have about using and distributing MPLed code.
If you see any errors in this FAQ, or have suggestions for further
questions, please email
Gerv.
- I want to distribute complete and unchanged binary packages compiled by
mozilla.org. What do I have to do?
-
Nothing. :-)
The mozilla.org-provided binary packages already meet
the requirements of sections
3.1 to 3.5,
and include the notices required by section
3.6. Although the MPL permits alternative
licensing for binaries, mozilla.org binaries are under the terms of the
MPL also.
If you are offering a warranty, you must make clear that it is
offered by you alone [3.5]. mozilla.org
offers no warranties on our binaries.
You do not require a
Mozilla
Foundation trademark license.
-
I want to distribute Mozilla (or other MPL-covered code) that I have
compiled myself but not changed. What do I have to do?
-
You must
-
add a conspicuous notice stating where to find the exact source to
the binary you are distributing
[3.6]
(Note: if you are compiling a Mozilla-like package, this may
be already included, e.g. in about:.)
- if your documentation has a section dealing with licensing or the
recipient's rights to the code, put a copy of the MPL in it.
[3.5]
You may distribute any binaries you create under a license of your
choosing, as long as it doesn't interfere with the recipients' right
to the source under the MPL [3.6].
You may require a
Mozilla
Foundation trademark license if you wish to use Mozilla
Foundation trademarks (e.g. the Firefox name or logo).
-
I want to distribute some of the component parts of
binary packages compiled by mozilla.org. What do I have to do?
-
You must
-
add a conspicuous notice stating where to find the exact source to
the binary you are distributing
[3.6]
- if your documentation has a section dealing with licensing or the
recipient's rights to the code, put a copy of the MPL in it.
[3.5]
The MPL allows distribution of binaries under any license, as long as
it doesn't interfere with the recipients' right to the source under
the MPL [3.6]
The mozilla.org binaries are also distributed under the MPL. This is a
slightly unusual arrangement; what it means practically is that you
must also redistribute them under that license
[3.1], and therefore allow
anyone else to redistribute the copy you gave them.
If this is a problem,
you should compile the binaries yourself, in which case you
may choose any binary license the MPL allows
[3.6].
You may require a
Mozilla
Foundation trademark license if you wish to use Mozilla
Foundation trademarks (e.g. the Firefox name or logo).
- I want to distribute a modified version of Mozilla (or other MPL-covered code).
What do I have to do?
-
You must
-
add a conspicuous notice stating where to find the exact source to
the binary you are distributing. [3.6]
If you wish, you may point at mozilla.org for the base code and then
ship diffs between our version and yours.
- if your documentation has a section dealing with licensing or the
recipient's rights to the code, put a copy of the MPL in it.
[3.5]
In addition, there are several obligations relating to your
Modifications. You must
-
have the right to distribute your Modifications
[3.4 (c)]
-
add a correctly-completed MPL header to any new files which are
Modifications [3.5]
-
make your Modifications available in source code form, under the
MPL [3.1]
-
make your Modifications available on the same media as the executable
version, or on the Net as long as they are available for 12 months
[3.2].
-
document what your Modifications are
[3.3]
(one way to meet this requirement is to ship them as diffs)
-
include a statement that your code is derived from the particular
piece of MPLed code you started with
(e.g. Mozilla), and a list of the names of the Initial Developers of
that code [3.3].
-
How 'viral' is the MPL? If I use MPLed code in my proprietary application,
will I have to give all the source code away?
-
The MPL has a limited amount of 'copyleft' - more copyleft than the
BSD family of licenses, which have no copyleft at all, but less than
the LGPL or the GPL. It is based around the
definition of a 'Modification' in the license
[1.9].
What is a Modification? Any
changes to MPLed files, or new files into which MPLed code has been
copied, are Modifications and so fall under the MPL. New files
containing only your code are not Modifications, and not covered by
the MPL.
Files which fall under the MPL because they are or contain
Modifications must be made available as detailed
in the license (or elsewhere in this FAQ.) Other files may be kept
proprietary.
One well-known example of this is the Netscape-branded browser. It
contains (and Netscape makes source code available for)
many files from the Mozilla project, which are under the MPL.
But it also contains proprietary code, for example
to integrate with the AOL Instant Messenger service.
-
May I combine MPLed code and BSD-licensed code in the same binary?
-
Yes. mozilla.org does this - for example libjpeg, which decodes JPEG
images, is under a BSD license.
-
May I combine MPLed code and GPL-licensed code in the same binary?
-
No, unless the MPLed code is also available under the GPL - for example
using the mozilla.org tri-license. This is because the MPL imposes
additional restrictions over and above those imposed by the GPL, which
makes it incompatible with section 6 of the GPL.
-
Who has the right to publish new versions of the MPL
[6.1]?
-
The Mozilla Foundation acquired this right from Netscape at the time
it was founded.