In Portuguese, “entendedores entenderão”, which literally can be translated to “those who understand understand”, is often used on the internet.
Someone might write this when (s)he posts something that only people with knowledge on the subject would be able to comprehend. For example, when posting a joke about mathematics.
Is there an idiomatic expression that means the same thing in English? I tried googling the phrase “whoever gets it”, hoping it would lead to some expression, but I did not find anything.