To go along with the other response, they don't own your copyright -- but I don't know if the language in the Python CLA actually holds them to the "we can only

To go along with the other response, they don't own your copyright -- but I don't know if the language in the Python CLA actually holds them to the "we can only relicense to open source licenses" if challenged in a court. But that's not really a risk I care about. The PSF is a nonprofit that's clearly aimed at being a nonprofit, and a Future Evil Board is beyond what I'm going to worry about.