''<p>pdpmonitor [[#question-1492800|said]]</p>'' <blockquote>stop notifications </blockquote> Those appear to be Web Push Notifications from one or more sites you have allowed to send you notifications. Unfortunately some may just send you junk, spam, fake virus and other alerts instead of useful information. You can revoke those sites. 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