We are interested in knowing whether reducing referrer headers from resources on the tracking protection list causes those resources to load with significantly different content. We would like to test origin only referrers as well as no referrers. We can measure this impact by diffing across three web crawls, two which don't block strip referrers and one which does not. As a first pass we can examine the scripts which serve the same content when referrers are present, but different content when referrers are stripped or origin-only.