Part P. Patent License
Part P lets the Licensor give specific inventions to the public good while keeping others to sustain the business that maintains the protocol.
P.1 Patent Schedule. The Licensor publishes a Patent Schedule with each Covered Work. It lists each patent and patent application the Licensor holds that bears on the Covered Work, and marks each claim, or group of claims, as either:
- Contributed: given to the public good under P.2; or
- Reserved: kept by the Licensor under P.3.
A claim not listed is Reserved.
P.2 Contributed Claims. The Licensor grants you a worldwide, royalty-free, non-exclusive license under the Contributed Claims to make, use, sell, offer for sale, import, and otherwise practice any implementation, to the extent it conforms to the Specification the claim is listed against. This license does not depend on Part W and is free for everyone, including commercial users.
P.3 Reserved Claims. No license is granted under Reserved Claims, except:
- Software licensees. While you hold and comply with a free or paid license under Part W, you may practice the Reserved Claims as embodied in the unmodified Software and its Derivative Works.
- Public-good covenant. The Licensor will not assert Reserved Claims against an individual or public-good organization under W.2 for research, teaching, standards review, or non-commercial use.
- Commercial license. Everyone else may obtain a license to Reserved Claims on the Licensor's published terms (W.8).
P.4 One-way ratchet. The Licensor may move a claim from Reserved to Contributed at any time by publishing a new Patent Schedule version. A Contributed Claim is never moved back to Reserved, and the license in P.2 for it is irrevocable except under P.5.
P.5 Defensive termination. If you, or an Affiliate, start or join a lawsuit or proceeding claiming that a Covered Work, a conforming implementation, or the Licensor infringes a patent, every license you hold under Part P ends on the date you file, and every license under Parts W and P ends for the Affiliate that files.
P.6 Grant-back. If you obtain or hold a patent claim that covers a Derivative Work of the Software, or an improvement you made to a conforming implementation, you grant the Licensor and every other licensee under this license a worldwide, royalty-free, non-exclusive license under that claim to use it with the Covered Works. If the improvement is a Recognized Lineage Node whose terms are Reserved (E.5), the grant to the Licensor is unchanged, and other licensees receive it on that node's published price instead of royalty-free.
P.7 No implied licenses. No patent rights pass except as Part P states, whether by implication, estoppel, or otherwise. Publishing a Specification under Part S grants no patent license.