I found it with the help of ChatGPT. Grok failed me.
It was called "Glue". This was long before Gab's Dissenter.
When I learned of this, I thought it would change the web as we know it. You could leave a trail of what websites you visitied. Again, I was wrong...
https://www.wired.com/2009/06/glue-goes-mainstream-with-new-internet-explorer-plugin/