TOM_RUS mentioned it to me on IRC, and I told Apoc via Skype. That is how they found out about it. I didn't mention it publicly because it didn't occur to me that anyone else would care. It's obviously not a secret. I don't think it counts as part of Warden, regardless of your definition of it. Warden loads a module which has its own .text segment, its own PE header, etc.. I haven't checked, but I assume the HB opcode does not have any code in the Warden data segment. To me, that means it is not a part of Warden.
Looks like this whole thread is done now, since the Warden module(s) have been more widely released.