Will is be US-based like Mozilla, or will it be somewhere else, like Europe?
A couple of foundations have moved away from the US in recent years, for example the Eclipse Foundation (Belgium) and the RISC-V Foundation (Switzerland).
It seems foundational (if you'd forgive the pun) to know under what laws the foundation will operate, and who (if anybody) will be excluded from taking part in the project because of sanctions regimes.
Our government has repeatedly made it policy to block access to software of domestic origin through export controls [0] [1]
Historically I'd argue most nations could trust the US government only to wield economic sanctions against our adversaries, but the current administration has made all nations our adversary.
I can see a real possibility of the current administration enacting export controls on the European Union for a perceived slight against the President, and Congress will not stop him. For example, if crates.io is an American-based software service, there is a real possibility that the US could ban the owners from allowing access from EU IPs.
Granted, the same is true of GitHub, npm, freaking google... but the tl;dr is that I don't think you can trust us today or tomorrow. I don't trust my government, why should you?
[0] https://techcrunch.com/2019/07/29/github-ban-sanctioned-coun...
[1] https://www.eff.org/deeplinks/2019/08/us-export-controls-and...
https://www.dw.com/de/us-senatoren-drohen-sassnitz-zu-schade...
US senators are threatening sanctions against the German harbor town of Sassnitz https://www.dw.com/de/us-senatoren-drohen-sassnitz-zu-schade... to prevent the nord stream gas pipeline from being built. They’d prefer if germany bought liquefied gas from the US. (It’s a bit more complicated than that, but the threat is a new escalation)