What doe double Asterisks (**) mean in Javascript config files? [duplicate]

For example those ** here:

purge: ["./pages/**/*.{js,ts,jsx,tsx}","./components/**/*.{js,ts,jsx,tsx}","./layouts/**/*.{js,ts,jsx,tsx}",],

in my tailwind.config.js

My guess woudl be that it would look recursively in all subfolders of the parent?