RBR stands for Ro7a Bala Raj3a which means GTG 😉 I first came to hear of it on a talk show in Jordan in a taxi many years ago now. But they were trying to come up with the best short hand msn abreviations and RBR came up and I was like WTF is that. Turns out Ro7a Bala Raj3a and I was like ohh snap.