Good idea, but No hide option or password protection.

Instead of having you advance and then deadend on a blank page, could you have it throw a little pop-up/toast saying that the page is blocked on the page without taking you away from the page you were on originally?

Ancestry, for instance, doesn't tell you which sources you can access for free and which ones they will harass you to pay for. This feature allows you to click the links and keep going down the line if you block the "give us money" page it redirects to if that resource is not available for free. Not having to backtrack and click again every time makes research go *much* faster.

It's currently got a strict_max_version set to Firefox 56 in the manifest. Which prevents it loading in Firefox 57. Is there a reason for that? You can just remove that line from the manifest and it will work on all future Firefox versions.