Whether it's actually anonymous in practice, and/or whether it starts to go further than that (websites asking for verified gender? First name? City? Full DOB?) will be a real concern but I think there'd be plenty of push back and tech will end up setting norms here through the browser APIs & permissions prompts. In theory in this is all covered under GDPR anyway so requesting or storing information that's not necessary is illegal anyway, and at least explicit requests are less secret than invisible tracking of the same thing - much easier to reject individually, and to litigate abuse collectively.
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