I suspect that sMartypants did the same typing tutorials that the Rickeybird did.That quick slick RicardoBird somersaults atop yon lazy dog, with nary a tribulation in the world.
Wikipedia
The "quick brown fox" is often used for touch-typing practice, testing typewriters and computer keyboards, and displaying examples of fonts. It can be used when all the letters in the alphabet need to be typed. Because the short sentence makes sense, it is widely known and used.