[jonarnes]

> The opt-in based mechanism of Client Hints currently suffers from the fact that on the very-first view, the browser have not yet received the opt-in. That means that requiring specific UA information (e.g. device model, platform) on the very-first navigation request may incur a delay. We are exploring options to enable the opt-in to happen further down the stack to avoid that delay.

I'm surprised Google goes ahead with this without having a concrete plan to handle the first request to a page. I fear that will become an ugly mess of redirects, js hacks and broken pages. Think Google is under estimating how widespread device detection user User-Agent on the server side is...