hello, only sites that you've set permissions that vary from the default settings in firefox in some form will show up in the permissions manager - also see Permissions Manager - Give certain websites the ability to store passwords, set cookies and more.

Thank you. However the link above says: "On the left hand side you'll see a search bar with a list of all the websites you've been to below it. The right hand side lists the various website permissions that Firefox stores."

It then says I must highlight a site to alter it from the default permissions. So I'm confused: how do I ever get to alter anything from the default permissions if it doesn't appear until altered? Is there some other way of altering them?

you can also access the permissions of a page when you're visiting it by right-clicking & going to view page info > permissions.

Firefox Page Info window

Thank you very much. That seems to work for me, even if it doesn't seem to correspond with the instructions on the support webpage.

While philipp's response was helpful, it did not address original poster's question. It would be better if this information was all consolidated, instead of having to do it one at a time, per page visit.

So simply -- Why is about:config not showing all visited sites?