User Agent Client Hints

[gsnedders]

Request for position on an emerging web specification

• WebKittens who can provide input: @othermaciej @johnwilander

Information about the spec

• Spec Title: User-Agent Client Hints
• Spec URL: https://wicg.github.io/ua-client-hints/
• GitHub repository: https://github.com/WICG/ua-client-hints

Design reviews and vendor positions

• TAG Design Review: User-Agent Client Hints & UA Reduction w3ctag/design-reviews#640
• Mozilla standards-positions issue: User Agent Client Hints mozilla/standards-positions#202

See also https://mozilla.github.io/standards-positions/#ua-client-hints.

Bugs tracking this feature

• WebKit Bugzilla: https://bugs.webkit.org/show_bug.cgi?id=241749
• Radar: rdar://95454627

Anything else we need to know

This builds on top of the infrastructure defined in #20. We've filed a variety of issues on both UA Client Hints and the infrastructure specs previously, but the only one that I believe is still open is WICG/ua-client-hints#151.

[othermaciej]

I think a resolution to WICG/ua-client-hints#151 is still important (I need to go back and look at what it says). Also need to look at the dependencies to ensure the base UA Client Hints spec doesn't effectively mandate implementing all client hints for browsers that implementing.

[othermaciej]

The privacy concerns are due to the unresolved issue, and for additional close reading by privacy experts.

The interoperability concerns are because the spec allows a wide range of more or less privacy protective behaviors (with resolutions to privacy issues often being to add a MAY rather than to change the required behavior), and it's possible sites may come to depend on behaviors that aren't required by the spec.

[miketaylr]

I'd be very happy to work with someone in the WebKit project to address the open concerns (and if there was interest to implement, we could move this out of WICG into something like webapps WG to make collaboration simpler).

[litherum]

What's the difference between this and #20?

[gsnedders]

What's the difference between this and #20?

See the comments on #20: #20 is about client hint general infrastructure, this is about the UA client hints, there are other issues filed for positions on other client hints.

[othermaciej]

Besides the earlier cited issue, I think this one was not actually addressed in a satisfactory way (I can’t figure out how to reopen it in GitHub) WICG/ua-client-hints#146

[hober]

We need to come to a position on #20 before we can come to positions on proposals that use the Client Hints infrastructure.

[miketaylr]

I think this one was not actually addressed in a satisfactory way (I can’t figure out how to reopen it in GitHub) WICG/ua-client-hints#146

Thanks, I've re-opened it.

[djmitche]

FYI, this Chrome feature tracks adding Sec-CH-UA-Form-Factor to UA Client Hints. I don't think this particular hint moves the needle on the overall position on client hints, but I'm happy to learn more.