[Minutes] UA String Reduction - 2022-10-14

Attendees:

Chris Peterson, Mozilla
Mike Taylor, Google
Karl suggests we invite John Wilander from WebKit team.
- Agenda?
  - Perhaps WebKit concerns with the UA-CH API Recent mentions of UA-CH in WebKit standards position repo: WebKit/standards-positions#70

[chris] I’m still prototyping the navigator.userAgentData API for Firefox in my spare time. Slow progress and no ETA. https://bugzilla.mozilla.org/show_bug.cgi?id=1750143
Use-counter data on hints: https://chromestatus.com/metrics/feature/popularity
Search for “clienthintsua” to find FullVersion, deprecated in favor of fullVersionList.
MDN docs
ClientHintsUAFullVersionList @ 18%
- Usage climbed in Feb-Mar, probably due to some analytics or fingerprinting script.
ClientHintsUAFullVersion @ 18%
- Usage spiked in Jan-Feb, probably due to some analytics or fingerprinting script. Interesting that FullVersion usage spiked before FullVersionList.
The top sites using the deprecated FullVersion are mostly Google Business mobile sites (like https://steakhouse-319.business.site/) and a few Wikimedia sites.
- Mike to take an AI to file a bug / investigate.
Mike in discussion with some internal teams to migrate to Full-Version-List. Hopefully that will drive down some usage.

Proposed Rollout Plan page
Fully-reduced UA opt-in OT was extended from M104 to M106.
Phase 5 rollout still planned for M107?
Mike: yep, see proposed Finch rollout here.
Begin roll-out of reduced Desktop UA string and related JS APIs (navigator.userAgent, navigator.appVersion, navigator.platform).

Firefox Android team is testing new UAs for tablets. Firefox currently sends a “Mobile” UA on tablets, which causes usability issues on some sites.
We’re debating whether to:
- Use a Linux desktop UA (like Safari on iPad)
- Use an Android-without-Mobile UA (like Chrome on Android tablets), e.g. “Mozilla/5.0 (Android 10; Mobile; rv:104.0) Gecko/104.0 Firefox/104.0” vs “Mozilla/5.0 (Android 10; rv:104.0) Gecko/104.0 Firefox/104.0”
- Android-without-Mobile gets desktop layouts on sites that sniff for “Mobile” and mobile layouts on sites that sniff for “Android”.
- It also allows sites to detect Android and promote their native apps or other Android OS features, like app intents.
  - Use cases: launch an app or share data to clipboard/etc?
- How can we find out how sites are using Android-without-Mobile?
  - Use a crawler script to diff content bodies returned for Android with and without Mobile?
    - https://miketaylr.github.io/arewedetectableyet/
- Look for tablet-optimized sites?

Mike will ask Karl about inviting John Wilander from WebKit team to discuss UA-CH.
Mike will file a bug about Google Business mobile sites (like https://steakhouse-319.business.site/) using deprecated FullVersion UA-CH.