Design Review #1091

#1091: Add prefetchCache and prerenderCache to Clear-Site-Data header

Opened May 12, 2025

こんにちは TAG-さん!

I'm requesting a TAG review of the feature for adding prefetchCache and prerenderCache values to Clear-Site-Data header.

We propose adding two new values to the Clear-Site-Data header to help developers target clearing the prerender and prefetch cache: prefetchCache and prerenderCache.

Explainer¹: https://github.com/WICG/nav-speculation/blob/main/clear-site-data-integration.md
Specification: https://wicg.github.io/nav-speculation/
WPT Tests: https://github.com/web-platform-tests/wpt/pull/52223
User research: none
Security and Privacy self-review²: https://github.com/WICG/nav-speculation/blob/main/clear-site-data-integration.md#w3c-tag-security-and-privacy-questionnaire-answers
GitHub repo:
Primary contacts:
Organization/project driving the specification: Chromium
This work is being funded by: Microsoft
Primary standards group developing this feature: WICG
Group intended to standardize this work: WHATWG https://github.com/whatwg/html/issues/11123 https://w3c.github.io/webappsec-clear-site-data/
Incubation and standards groups that have discussed the design: https://github.com/WICG/nav-speculation/issues/357
Multi-stakeholder support³:
- Chromium comments: https://chromium-review.googlesource.com/c/chromium/src/+/6456388?tab=comments
- Mozilla comments: https://github.com/mozilla/standards-positions/issues/1214
- WebKit comments: https://github.com/WebKit/standards-positions/issues/488
Major unresolved issues with or opposition to this specification: None
Status/issue trackers for implementations⁴: https://chromestatus.com/feature/4755745652080640

Further details:

I have reviewed the TAG's Web Platform Design Principles
Previous early design review, if any: https://github.com/w3ctag/design-reviews/issues/####
Relevant time constraints or deadlines:

Discussions

Discussed May 19, 2025 (See Github)

Martin: I think we can say "thanks for coming" on this. It's just maintenance. We may as well say it's ok.

Torgo: where is it going? positive feedback from other implementers?

Martin: it does from Mozilla, I think

Jeffrey: yes, simon has replied. There is one concern that clearsitedata doesn't have a place to land.

Martin: so one way to do that is simply say in your own spec, this is it. the prefetch specs could modify the clearsite stuff.