Topics API - feature overrides based on etld+1 ?

[relevance-api-topics]

Hi experts, we are having trouble to fetching topics for the below case:

• observe topic via fetch call to server1.region.test.com, chrome://topics-internals/ has test.com recognized the observer.
• however, when document.browsingTopics() on server1.region.test.com, nothing obtained.
• only when adding server1.region.test.com to chrome://flags/#privacy-sandbox-enrollment-overrides, topic can be fetched.
• Question: we already added test.com into chrome://flags/#privacy-sandbox-enrollment-overrides, isn't it be used for server1.region.test.com, server2.region.test.com... serverN.region.test.com, directly? Otherwise every server need to override for testing.

Is anything missed from our side, or this is an issue to update? Thanks!

[xyaoinum]

Both the observation and the enrollment rely on etld+1.

Adding test.com to chrome://flags/#privacy-sandbox-enrollment-overrides should be sufficient for your case. Also, calling fetch('https://server1.region.test.com', {browsingTopics: true}) should produce the same results as calling document.browsingTopics() within a frame on https://server1.region.test.com.

Are you seeing differences between these two methods, or are neither working as expected? It would be helpful if you could provide detailed reproduction steps. If possible, please consider filing a bug report.