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Apple already shipped attestation on the web, and we barely noticed
(httptoolkit.com)
This is a most excellent place for technology news and articles.
I consider myself a rather avid technology reader and try to stay up on the trends and this one completely escaped me, I am sorry to say.
It was part of the same keynote speech where Apple announced their virtual reality headset... so the media largely didn't cover it.
But Apple absolutely did announce it, and as loudly as they possibly could with a high profile executive standing on stage before a live (online live, but still live) audience of millions of people and every tech journalist in the world to demo the feature. There's also extensive documentation and whitepapers covering how the crypto works, and I expect it was discussed on public mailing lists ahead of time (I don't follow those mailing lists - they're too busy, so not sure about that one).