Did you just open Firefox only to find all of your extensions disabled and/or otherwise not working?
You’re not alone, and it’s nothing you did.
Reports are pouring in of a glitch that has spontaneously disabled effectively all Firefox extensions.
Each extension is now being listed as a “legacy” extension, alongside a warning that it “could not be verified for use in Firefox and has been disabled”.
A ticket submitted to Mozilla’s Bugzilla bug tracker first hit at around 5:40 PM Pacific, and pins the sudden failure on a code signing certificate built into the browser that expired just after 5 PM (or midnight on May 4th in UTC time).