Apply the rules
Inspect a real distribution using Mozilla Public License 2.0. Identify its license version, required notices, upstream dependencies and any unresolved permissions.
Licenses / Knowledge library
Mozilla Public License 2.0
Understand Mozilla Public License 2.0: permissions, conditions and limitations.
Why learn Mozilla Public License 2.0?
Make informed reuse and redistribution decisions under Mozilla Public License 2.0; this lesson is not legal advice.
The problem it solves
Explains the obligations that a license label alone can hide. Verify the exact version and upstream terms.
Where it came from
What copyleft scope is commonly associated with MPL-2.0? (Mozilla Public License 2.0) Covered source files. Can MPL-covered files be combined with separate proprietary files in a larger work? (Mozilla Public License 2.0) Yes; satisfy the covered-file obligations. When distributing modified MPL-covered source, which license applies to those covered files? (Mozilla Public License 2.0) MPL-2.0 subject to its terms. What must executable-form recipients be told about MPL-covered source? (Mozilla Public License 2.0) How to obtain the source under the required terms. Does MPL-2.0 grant unrestricted rights to contributor trademarks? (Mozilla Public License 2.0) No.
- What copyleft scope is commonly associated with MPL-2.0? (Mozilla Public License 2.0) Covered source files.
- Can MPL-covered files be combined with separate proprietary files in a larger work? (Mozilla Public License 2.0) Yes; satisfy the covered-file obligations.
- When distributing modified MPL-covered source, which license applies to those covered files? (Mozilla Public License 2.0) MPL-2.0 subject to its terms.
- What must executable-form recipients be told about MPL-covered source? (Mozilla Public License 2.0) How to obtain the source under the required terms.
- Does MPL-2.0 grant unrestricted rights to contributor trademarks? (Mozilla Public License 2.0) No.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- What copyleft scope is commonly associated with MPL-2.0? (Mozilla Public License 2.0)
- Can MPL-covered files be combined with separate proprietary files in a larger work? (Mozilla Public License 2.0)
- When distributing modified MPL-covered source, which license applies to those covered files? (Mozilla Public License 2.0)
- What must executable-form recipients be told about MPL-covered source? (Mozilla Public License 2.0)
- Does MPL-2.0 grant unrestricted rights to contributor trademarks? (Mozilla Public License 2.0)
More ways to practice
Documentation and sources
- Official specification / license documentation (www.mozilla.org)
Catalog research notes
- Learning notes checked October 13, 2026. Consult the official source for subsequent changes.
Connect the ideas
Explore next
Real World Example
Integrating Open Source Modules into Proprietary Analytics Suites
Software vendors building proprietary analytics platforms that incorporate open-source libraries.
The business problem
The vendor needs to use a high-performance open-source library but fears that standard copyleft licenses might force them to open-source their entire proprietary codebase, which contains trade secrets.
How this topic solves it
The Mozilla Public License 2.0 (MPL 2.0) is a file-level copyleft license. It allows the vendor to integrate MPL-licensed code into a Larger Work while keeping the proprietary portions closed, provided that modifications to the original MPL-licensed files remain under the MPL 2.0.
- Identify the specific files governed by the MPL 2.0 within the library.
- Maintain the original license notices and copyright headers in all modified MPL-licensed files.
- Ensure that any modifications made to the MPL-licensed files are made available in Source Code Form.
- Distribute the proprietary analytics suite as a Larger Work, keeping the proprietary source code private while providing access to the modified MPL-licensed source files.
Shows how proprietary and MPL code coexist in a Larger Work.
Original open source code
Changes made by vendor
Closed source logic
The final analytics product
- MPL Library → modifies → Modified MPL File
- Modified MPL File → includes → Larger Work
- Proprietary Module → includes → Larger Work
Expected business outcome
The vendor successfully leverages external open-source innovation to enhance their analytics suite without compromising the intellectual property of their proprietary modules.
Limitations and checks
The primary limitation is the file-level copyleft requirement. If a developer modifies an MPL-licensed file, that specific file must remain under the MPL 2.0. To verify compliance, the vendor must perform periodic audits of their build pipeline to ensure no proprietary code was accidentally merged into an MPL-licensed file.