how to stop pop ups

https://support.mozilla.org/en-US/kb/push-notifications-firefox#w_how-do-i-revoke-the-notifications-permission-for-a-specific-site Are these as small popups on bottom right corner of Firefox window?. If so then these may just be web push notifications from sites you have allowed to send you web push notifications. You can revoke the sites from sending you notifications as shown in KB article link above.