Don't know where it came from. There was no word of it anywhere on booru.org, but it was apparently a global update, as every booru has it now. (And in traditional fashion, it doesn't work 100% correctly :P)
I'd rather they fix the errors elsewhere before they add new features. :P But hey, free host and all that, who am I to complain? It's good to see that they continue to have an active interest in the booru project, in any case.