What is frog whistling?

I wonder if it means the same thing as "dog whistle" (as in a signal to your political base that doesn't literally translate to others) but for the Pepe the Frog white nationalist crowd.

There are no uninteresting things, only uninterested people. – G.K. Chesterton

It's a rather smart joke, combining the Trump camp's creepy infatuation with the Pepe frog meme and their susceptibility to be easily manipulated by dog whistle techniques.