Meta, Google, Apple and Mozilla are defining Attribution Level 1 as a built-in browser feature for correlating ad impressions with conversions via aggregated reports sent to centralized services. Primary source: https://blog.zgp.org/the-advertising-cartel-coming-to-your-web-browser/. Related coverage in W3C Incubation reports and Google’s Attribution Reporting API documentation confirms the absence of per-user consent flows. The API records impressions client-side and generates conversion reports that feed an aggregation service while aiming to block cross-site recognition. Industry documentation from the Private Advertising Technology Community Group shows the same entities advancing parallel proposals for fenced frames and topics APIs. Technical specifications limit outputs to aggregate statistics, yet leave integration with existing first-party data stores unaddressed in the core draft.