Thicket von Rayen

Allows you to mark a site as visited, storing the URL using one-way encryption (hashing).
This allows you to know confidently if you have seen a site before without keeping a giant list of bookmarks, histories or URLs.

When marked, the extension in the icon toolbar changes. There is no other notification.

The tabs permission is needed to refresh the icon and know when you have moved to a new page only.