That's not a joke.
We all heard about that developer made of coffee and soda, many tried it, and the results with this homebrew (!) are not bad.
I just wonder why there is a company that makes a sophisticated commercial product based on Caffenol?
Such a provider might use well-controlled, high-quality chemistry, let's say pure caffeine acid, soda, pure ascorbic acid, maybe some addons that make the process more reliable and exploit the capabilities of this only environmentally friendly "stain" developer.