User-Agent 👀 Client Hints

[via JavaScript] [via headers]

[Response] Server asked for:

Accept-CH: save-data, ch-save-data

[Subsequent Request] Client sent:

[…]

[For comparison] User-Agent:

[…]

Server should ask for:

Available hints Sec-CH-UA-Arch Sec-CH-UA-Bitness Sec-CH-UA-Full-Version Sec-CH-UA-Full-Version-List Sec-CH-UA-Mobile Sec-CH-UA-Model Sec-CH-UA-Platform-Version Sec-CH-UA-Platform Sec-CH-UA-Wow64 Sec-CH-UA

Do not send Accept-CH

*️⃣ Requires Chrome 84 or equivalent.
📃 Read the proposal at github.com/WICG/ua-client-hints
💻 See the demo code.