It's sounding like California is going to require browser manufacturers to support the GPC signal. The privacy movement in California has a lot of political power and backing; it's pretty likely this will change in the next couple years.
From what I understand, their AG has said the GPC signal must be honored if sent and that it is an acceptable opt-out mechanism under the CCPA. I haven't heard anything concrete about requiring browsers to support it, but that would be a welcome development.
California's "Opt Me Out Act" (AB 566) requires that by January 1, 2027, internet browsers must provide a built-in, easy-to-use setting that allows users to send an opt-out preference signal, such as Global Privacy Control.
(copied from a search, but wanted to let you know)
