What Mozilla Accounts are used for besides this support.mozilla.org site https://support.mozilla.org/en-US/kb/access-mozilla-services-firefox-account#w_what-services-can-i-use-with-a-mozilla-account It is possible to use the Firefox web browsers for desktop and mobile versions for Android and iOS/iPadOS without using a Mozilla Account at all or very little. Since you have used your Mozilla Account to login on this support.mozilla.org site it should be considered active now and the emails notifications should stop. https://support.mozilla.org/en-US/kb/mozilla-account-deletion-inactivity