It seems shortsighted to define the age bracket API specifically around California's chosen four brackets. Why not merely return two integers bounding the age bracket, so that the API can adapt to different regulatory environments?
An official response from Ubuntu:
https://discourse.ubuntu.com/t/ubuntus-response-to-californi...
The email linked here are ideas from an Ubuntu contributor, not an official response.
Do we know whether any Linux distributions will be refusing to implement anything like this?
Perhaps they should release a "Kids" version of Ubuntu for regions where age verification is important.
Use it as an opportunity to promote the "Ubuntu Core" architecture (i.e., "immutable" Ubuntu) just like Microsoft did with Windows "S" editions.
Easy, "For legal reasons, this OS is not available in California"