Expired certificate broke all Firefox add-ons

What just happened? On Friday night as the clocks struck midnight, users of Mozilla's Firefox browser discovered that any add-ons they had installed no longer worked. Mozilla have ascertained that an expired security certificate is to blame and a hotfix is being deployed now.
Read more: https://www.techspot.com/news/79937-expired-certificate-broke-all-firefox-add-ons.html?source=Snapzu