As an Caltex employee....Caltex (the petrol retailer) was jointly owned by Chevron and Texaco of the U.S. and was (and still is) in some countries a brand name (and little more).
Chevron and Texaco merged quite a few years ago but have generally kept marketing fuel using the various brand names they have between them.
I'm not one who believes there is much if any different between brands, well in NZ anyway, but the oil companies spend a lot of difference convincing us there is.....
I find 95 octane (of any brand) works fine in my A10 (flat top piston so not high comp) , but if I happen to pass a BP or Gull station with 98 octane I'll put that in, if provoked I can get it to pink on 91, so I avoid putting that in it.