We discussed in planning today that it would be nice if these headers were set per domain. Maybe the "podium/init" message sent by headers.js can include the URL so we can use it as a rule condition here (urlFilter perhaps)?
The same condition has to be set in onUpdateHeaders on L117.
We would have to filter out the correct rules in activeRules on L89 as well, so the UI doesn't show the rules for another domain.
We would also need to generate and keep track of rule IDs, not hard code to 1.
From #76