@VirginiaPoundstone another task to decline or resolve?

Oh, or perhaps the subtasks should be done first?

I've been bold and removed two subtasks that I don't think are related to this epic. T267217: MediaWiki Session ID should have per-subdomain and cross-subdomain variants is a feature request for someone – I don't think there's formal ownership of session IDs but Data Products does seem like a good fit so I've tagged it as such. T267602: Client-side error logging should use Elastic Common Schema (ECS) fields when possible isn't related to Metrics Platform work.

I can see a future in which we use client-side error count as a guardrail but that's an epic in and of itself since we have to consider filtering errors caused by user scripts, gadgets, and banners, which is non-trivial (see T361680: CentralNotice should catch banner errors and log them to its own channel).