I’d personally just delete all of the stored data, and watch when I load the page to see what gets created.

If the same domain is being affected across multiple tabs, it’s possibly related to multiple tabs trying to access the local storage at the same time. You can see that data from the dev tools built into Firefox (hit F12). https://firefox-source-docs.mozilla.org/devtools-user/storage_inspector/

Yup. The tracking stuff just makes it easier, but standard use of the phone sans tracking is still trackable.

Looks like they stopped dev in '21, but RockBox is what I used to use. Amazing software.