Additionally, contributions to these projects are no longer governed by a CLA but instead by the Linux Foundation’s DCO. This should simplify the contribution process. If you are not familiar with the DCO, the various projects mentioned above contain a CONTRIBUTING.md file explaining how to proceed when submitting pull requests.
This move was motivated by the desire to use a simpler license and to simplify the contribution process. The previous license was Apache 2.0 and prevented use of our projects by others on a few occasions.
A big thanks to the Jane Street Legal and Compliance team who did all research work to find out whether the combination MIT+DCO was a suitable replacement which made this change possible.