Yep, basically the light is letting you know the car has kicked into 'performance' shift patterns for the automatic. Yes, you are mashing on the gas pedal!
I can't remember exactly when they disabled that feature, sometime during the mid 90s. My 90 Legacy has it, my 93 SVX had it, but I don't think my wife's 96 Outback does. They disabled it because it confused consumers. Hmmm... what's that light on my dash? It must mean trouble!