Hmm I wonder if these are web push notifications from one or more sites you have allowed to send you notifications. Perhaps you can revoke the site(s) sending you these notifications. https://support.mozilla.org/en-US/kb/push-notifications-firefox https://support.mozilla.org/en-US/kb/push-notifications-firefox#w_how-do-i-revoke-web-push-permissions-for-a-specific-site

James, Thank you for responding. The notifications are only for Emails that somehow are prioritized. If I could undo the "prioritizing" I think the problem might go away.