Well damn. I still have a couple cans in the garage, the feds will just have to come for me. :-)
The Super Blue issue came up a couple of months or so ago. iirc, the manufacturer “voluntarily” withdrew Super Blue from the market due to this federal rule (which, i indrrstand, has actually been in place for a loooong time). The rationale for the rule is supposedly to prevent meemaw from confusing brake fluid with, idk, windshield wiper fluid, and adding windshield wiper fluid to her brake fluid reserve.
I noticed recently that one of my preferred online parts dealer lists Super Blue as “no longer available” on their website. But undoubtedly plenty of customers like you (and retailers) didn’t get the memo. On the other hand, a trackside vendor hawking racing gear at a road course the past couple of weekends had some cans of Super Blue for sale on a shelf.
FWIW, if you do a LOT of threshold braking (I do), I highly recommend Castol SRF. Good stuff. Minimal fade. Seems to last me awhile.