Mozilla Public License facts for kids
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| Author | Mozilla Foundation |
|---|---|
| Version | 2.0 |
| Copyright | Mozilla Foundation |
| Published | January 3, 2012 |
| DFSG compatible | Yes |
| Free software | Yes |
| OSI approved | Yes |
| GPL compatible | 2.0 and later: Yes (by default, unless marked as "Incompatible With Secondary Licenses") 1.1: No |
| Copyfree | No |
| Copyleft | Yes, file-based |
| Linking from code with a different license | Yes |
The Mozilla Public License (MPL) is a special set of rules for computer programs. It's a type of free and open-source license. This means anyone can see, use, change, and share the program's code. The MPL is used for many Mozilla Foundation programs, like Firefox and Thunderbird.
Mozilla created and looks after the MPL. It tries to find a good balance between people who want all software to be open and those who want to keep some parts private. It's like a middle ground between very open licenses (like BSD) and very strict ones (like the GNU General Public License). With the MPL, you can use parts of a program that are under this license in your own private programs. But you must keep the MPL parts open for everyone to see and use.
Other companies and projects also use the MPL. For example, Adobe used it for their Flex programs. The Document Foundation also used it for LibreOffice 4.0. An older version, 1.1, was even used to create other similar licenses. The MPL has been updated twice. Version 1.1 was a small update, and version 2.0 was a big update. The goal was to make it simpler and work better with other licenses.
Contents
What the MPL Allows and Requires
The MPL gives users many rights. It lets you freely use, change, share, and even make money from the software. These rights come from "contributors," who are the people who write or change the code.
Using and Sharing Code
You can use the code for almost anything you want. However, you can't use a contributor's brand name or logo without permission. Your rights to use the code will stop if you don't follow the license rules. But if you start following the rules again, you get your rights back.
The license also has a rule to protect people from "patent trolls." These are people who try to unfairly sue others over ideas. The original creators of the code don't promise that the software will work perfectly. They also aren't responsible if something goes wrong. But other people who share the software can offer their own promises or support.
Keeping Code Open
When you share software that uses MPL code, you have certain duties. Any part of the code that is under the MPL must stay under the MPL. You can't try to stop others from using or changing it. The MPL looks at each computer file. If a file has MPL code, the whole file must stay under the MPL.
You can combine MPL-licensed code with other code that has different rules. This can create a "larger work." You can share this larger work under any rules you want. But remember, the original MPL-covered files must always be available for free. This makes the MPL a good choice for businesses and open-source groups. It lets them work together to improve core software.
Working with Other Licenses
There's one special case for MPL version 2.0. If MPL 2.0 code is mixed with code under certain GNU licenses (like GPL or LGPL), the whole program can be under the GNU license. However, the MPL-covered files will still be available under the MPL too. This means people can choose which license they want to use for those files. The original author of MPL code can choose to opt out of this special rule.
You can always share MPL-covered code under the version you received it or any newer version. If you update code from MPL 1.0 or 1.1 to 2.0, you might need to add a special note. You can also change the MPL to create a new license. But this new license can't use the names Mozilla or Netscape.
History of the MPL
The first version of the MPL, 1.0, was written in 1998. It was created by Mitchell Baker, who was a lawyer at Netscape Communications Corporation.
Netscape's Open-Source Plan
Netscape wanted to make its web browser, Netscape, open-source. They hoped this would help them compete better with Microsoft's browser, Internet Explorer. Netscape created a license called the Netscape Public License (NPL). This license had a rule that allowed even open-source code to be made private later.
At the same time, Mitchell Baker also created the MPL. It was named after Netscape's project name for its new open-source code. The MPL was first meant for software that added to the main parts covered by the NPL. But the MPL became much more popular than the NPL. It even got approval from the Open Source Initiative, a group that checks open-source licenses.
Updates and Improvements
Less than a year later, Baker and the Mozilla Organization made some changes to the MPL. This resulted in version 1.1, a small update. They asked for ideas from many people and groups. The main goals were to make the rules about patents clearer. They also wanted to allow "multiple licensing," meaning software could be under more than one license. This helped people work with developers who preferred stricter licenses. Version 1.1 also influenced later versions of other popular licenses, like the GPL.
Older versions of the MPL (1.0 and 1.1) didn't work well with the GPL. Because of this, the Free Software Foundation, a group that supports free software, advised against using MPL 1.1. So, older versions of Firefox were released under three licenses: MPL 1.1, GPL 2.0, and LGPL 2.1. Some old software, like the Mozilla Application Suite, still uses these three licenses.
MPL 2.0: A Major Step
In early 2010, after more than ten years, work began on MPL version 2.0. For almost two years, the MPL was changed to be clearer and easier to use. It was also made to work better with the GPL and Apache licenses. Mitchell Baker oversaw the team, and Luis Villa led it. They released several test versions before the final version 2.0 came out on January 3, 2012.
Programs Using the MPL
Many popular programs use the Mozilla Public License. Here are some examples:
- Apache Flex (used to be Adobe Flex)
- Armadillo (a C++ library)
- Boulder (the software that runs Let's Encrypt, which helps make websites secure)
- Cairo (a graphics library)
- Celtx (software for making movies and videos)
- Cemu (a video game emulator)
- Eigen (another C++ library)
- H2 (DBMS) (a database program)
- Internet Systems Consortium (a group that makes internet software)
- LibreOffice (a free office suite, like Microsoft Office)
- Mozilla Firefox (a web browser)
- OpenMRS (software for medical records)
- Syncthing (a file syncing program)
- Servo (a web browser engine)
- Brave Browser (a web browser)
- MonetDB (a database program)
- RabbitMQ (software for sending messages between programs)
- VLC (iOS Version) (a media player for Apple devices)
Licenses Based on Older MPL Versions
Some other licenses were created by changing older versions of the MPL (before version 2.0).
- AROS Public License 1.1 (from MPL 1.1)
- Common Development and Distribution License
- Common Public Attribution License
- Erlang Public License 1.1 (a changed MPL 1.0)
- Firebird's Initial Developer's Public License (from MPL v1.1)
- Sun Public License
- Yahoo! Public License
- Openbravo's Openbravo Public License (from MPL v1.1)
See also
In Spanish: Mozilla Public License para niños
- Software using the Mozilla license (category)
- Comparison of free and open-source software licenses
