Nobody wants to deal with the legalities of software development, but they are a fact of life. Without licenses and a clear understanding of copyrights using an Open Source project would be impossible for individuals and companies alike. To ensure that everybody can use libraries and code from the Pallets Project here are the rules with regards to how we handle licenses and individual code contributions:
All pallets libraries are licensed under the same three clause BSD license. This license was chosen a long time ago and for consistency we want to continue using this license going forward.
We never did copyright reassignments or CLAs and we will continue not doing this. Our contributors are from all parts of the world and copyrights are something that are mostly covered from an American legal point of view which often does not translate well into other jurisdictions. If you contribute to Pallets projects you contribute to it with the understanding that your own contributions are also provided under the same license as the Pallets project.
Some parts of the projects might follow slightly modified licenses. For instance website content and documentation might fall under CC0 or similar licenses.