As a follow up to Postmortem 392, https://docs.google.com/document/d/15hELat75YwHK4r_ThyZQ3MYhXzHmdcVR_eKEzjq17rg/view, an action item is working with the QA team to explore "parallel testing" of old and new revisions, with the aim of finding more bugs before they reach Stable.

Catching paint issues in pages that are unfamiliar to the tester can be challenging if the failure is of omission and the omission does not obviously affect the site. By comparing rendering across revisions should make failures clearer.