What does GBY mean on Snapchat?

I'm curious, what exactly does GBY stand for on Snapchat? It seems to be a popular acronym among users, but I'm not quite sure of its meaning. Could it be a reference to a specific inside joke or slang term? Or perhaps it's a shorthand for a more formal greeting or farewell? I'd love to get a clearer understanding of what GBY means and how it's used within the Snapchat community.