Mozilla Public License
Several versions of the Mozilla Public License exist. Our projects only use version 2.0, and this documentation likewise only talks about that version.
We don't use version 1.1, or any other past (or future) version of the MPL.
We use the Mozilla Public License (the MPL) for projects we feel are less important, less likely to be stolen from, good learning resources, or where a more permissive licence than the EUPL makes sense.
This includes our Gradle plugins, and our internationalisation toolkit.
About the Licence
According to Mozilla, the MPL is a simple copyleft licence, intended to be applied to individual files rather than sitting at the root of a project. This makes it easier for users and contributors to modify project code, while still allowing them to combine it with code under other licences with minimal restrictions.
It sits in-between the Apache licence and the GNU family of licences, providing a middle ground for projects that wish to use it.
Our Mindset
This section encompasses our own opinions. We're sure some people will disagree with us, but we're firm in our beliefs — so find something else to spend your energy on other rather than trying to change our minds!
In many ways, we treat the MPL as a lighter version of the EUPL. While we feel strongly about the culture of exploitation that is a necessary part of the open source movement, we recognise that a restrictive licence with strong protections isn't suitable for every project or situation. We apply the MPL to projects in those situations.
We feel that it is important to maintain developer freedom in many situations. Using a stronger licence for a library (or some other project types) would significantly impact developers' ability to maintain their own projects as they see fit.
Despite this, we feel that the MPL provides strong enough protections to stop malicious developers from taking advantage of us in most of the situations we care about.
Our Interpretation
Despite being a relatively permissive copyleft licence, the MPL does provide one important distribution requirement: all public distributions must include a link to the source code. If the distribution includes a modified version, the source code for that modified version must also be available and linked to.
Notably, the licence considers methods of distribution that add cost and complexity without a specific, necessary purpose as unreasonable, and these methods of distribution don't meet the licence terms. For example, you can't meet the licence terms by only distributing source code via a courier or other physical mechanisms, when you could more easily upload the source code to a website and provide a link.
Unlike the EUPL, "distribution" only covers situations where you deliver a copy of the software in question to another person or entity. It doesn't include a "network use" clause, so making the functionality available over a network doesn't trigger the distribution requirements.
Otherwise, this is a fairly standard copyleft licence, and we recommend reading the licence text yourself.
Questions and Concerns
If you have any questions regarding Kord Extensions and its licencing, please feel free to contact us via any of our community spaces.
If you have any questions about the MPL's wording or how to use it, Mozilla provides an in-depth FAQ, as well as a contact email address on the overview page.