Re:87% of American teens own an iPhone; 88% expect an iPhone...
by iamthirsty on Wednesday October 12, 2022 @06:22PM
(#33184445)
RCS is an open source protocol that can be run by different 'operators'[0]. So it's not so much as an extension, as Google's implementation of the protocol (which is open source and can be added by other operators).
[0]: https://en.wikipedia.org/wiki/Rich_Communication_Services