Step 1: Interact with the links below to grant heuristic exceptions to the domains listed.
Open and interact with the page (no opener access, but prior interaction with origin needed for window.open test below)
anchor tag popup with opener access (should grant on interaction with resulting page) -- disabled in Nightly
Step 2: Visit the page below to load the (now unblocked) trackers
Page that embeds the trackers granted by heuristics above