EXCELLENT question, never gave it a thought - Leaded and Ethanol (Public Board)
I had forgotten about the additives. There was a period when I was adding additives to the tank of my leaded petrol car after leaded petrol was banned completely. Pain in the arse. I guess if you have a vintage car it is worth the effort.
Interesting photo in the article. 87/89/91 octane. Ours are 91/95/98 (plus E10 plus diesel plus possibly others). But we don't have selector buttons, we have separate hoses for each of the available fuels, which vary from station to station and brand to brand. Modern bowsers have multiple hoses side-by-side with a single digital price display for the nozzle removed from its receptacle. So are those low octanes typical there?