Instrumentation has been implemented in T403255: Instrument image browser's primary metric, T403259: Instrument image browsing interactions, and T405489: Instrument image browser's guardrail metric.

Acceptance criteria

[] Beta: verify that all instrumented events fire - blocked by T408095: The `X-Experiment-Enrollments` HTTP header isn't honored on the Beta cluster

• • page-visit for measuring retention isn't currently fired. It's implemented in WikimediaEvents, where imageBrowsingPageVisit.js isn't loaded. Submit a fix
• Production
  • override enrollment as follows:
    • go to a target Wikipedia page - French example, Chinese example
    • in the browser's JavaScript console, override enrollment with mw.xLab.overrideExperimentGroup( 'fy2025-26-we3.1-image-browsing-ab-test', 'image-browsing-test' );. this should reload the page and enable image browsing

[] check they are all fully decorated with the experiment and experiments fields. - this isn't possible, since events are logged to the browser's console and only contain action and interactionData fields, as per docs

• this isn't happening. Convert mw.eventLog.submitInteraction calls to Experiment#send()

[] check that all events are produced on the eqiad.mediawiki.product_metrics.readerexperiments_imagebrowsing and codfw.mediawiki.product_metrics.readerexperiments_imagebrowsing Kafka topics - this isn't possible.
[] check that all events are collected in the Data Lake at event.mediawiki_product_metrics_readerexperiments_imagebrowsing - this isn't possible.