Third-Party Add-ons Many open source projects seek to add useful functionality on top of Protocol Buffers. For a list of links to projects we know about, see the third-party add-ons wiki page. Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 3.0 License, and code samples are licensed under the Apache 2.0 License. For details, see our Site Policies. Last updated September 3, 2014.