CLA stands for Contributor License Agreement. It is a legal document that some open source projects require contributors to sign before they can contribute code.
The primary purposes of a CLA are:
For permissively licensed projects, contributors do not need to sign a CLA given that permissive license terms govern the use of such contributions. Read more about permissive licenses Licenses.
For all other repositories, including (a) proprietary or (b) copyleft-licensed projects, contributors need to sign a CLA.
Read more about copyleft licenses Licenses.
We decided not to add CLAs to permissive open source projects to onboard contributors faster and show that we are committed to keeping the project open source.