https://en.wikipedia.org/wiki/List_of_English-language_gener...
I suppose they're in California really, but perhaps not for legal purposes. Likewise Uniregistry (.lol) "was registered in the Cayman Islands", for what good that does.
Generic TLD are different. ICANN dictate to different degree each generic TLD, and is also the one that give accreditation to registrars. ICANN has given different companies the role of operating and handling databases and registration systems, like Verisign with .com, but it is still ICANN that dictate policy. ICANN could decide tomorrow that Verisign is no longer suitable to run the operation of generic TLD's and thus move it to a company located in a different country.
Moving the operations of generic domains to a less US-centric location is not a new idea, same with the legal locations of the organizations that are ICANN and IANA. As I understand it, they are mostly located in USA as a matter of history.
In concept, IANA and the group of global stakeholders could move the whole thing to a different country if US becomes too much trouble.