Cannot find blink feature in the blink_features.usage table

Hi, I added a blink features to be tracked via UseCounters in Chromium a few months ago, and there is usage data in Chrome Status pages (0.6%): CrossBrowsingContextGroupMainFrameNulledNonEmptyNameAccessed.

However, the query result it empty when I try to query it from the httparchive.blink_features.usage table.

I think this is a different issue from How to get new/recent features added to the blink_features.usage table? because I can see this featured in the internal/support/ (wptagent/ at e0152a9094813276594426fb4fb82a58ed3d4e1a · WPO-Foundation/wptagent · GitHub) and it’s been available in Chrome stable since M86 (since Oct. 2020).

Does anyone know why is that?

I’m also interested in this, but for feature 3580. Thanks!

Is it possible that these features are inapplicable in a lab environment like HTTP Archive because they require real-user configuration/interaction? For example PreferredColorSchemeDark may never be counted if our test agents don’t set a preference for dark mode.

Thanks for the reply! My feature should be triggered when a navigation happens and the meets some requirements, for instance a navigation from (not blank page) to that’s initiated from the url bar should trigger the counter. Does the navigation from to require real-user interaction? Or is the “initiated from the url bar” part where the problem is?

Ah ok, no I don’t think the way we test each page meets those requirements. IIRC we load each page by first visiting about:blank, @patmeenan can confirm. Even if we did load each page sequentially (,, etc) wouldn’t that cause the feature to be counted on N-1 pages? and would that be useful to you?

Correct. We don’t use the URL bar to navigate. We use window.location so we can align start times with a video capture (removing the orange overlay in a RAF callback before setting the location).

If pages can be loaded sequentially from to, the feature will be counted while loading (why do you think it’s N-1? just want to make sure I understand your question).
Thanks for the information! If all the navigations are renderer-initiated and start from about:blank then that explains why the feature is not caught…

Thanks for the info!

I just meant that if we load then from the URL bar etc for a total of N URLs, then the feature would be counted on all URLs but the first, or N-1.

I see. There are other requirements for the feature to be counted, and if any site sets the property then it won’t be counted.