Just Sharing This Brake Master Cylinder Trick

I recall reading (can't remember where, of course) that DOT 5 should "not" be used with disc / drum, only disc / disc systems. Also, can't remember why. Big help here right? Do some research before inadvertently swapping DOT, or other, fluids just to be safe

It's been researched to death and argued for decades. DOT5 is safe in any non abs system that doesn't spec mineral oil