Ogg Skeleton is a multimedia container format. It is a subformat and extension of the lower-level Ogg container format. It defines a uniform way to, for example, put both an audio and video stream in the same file.
It defines a "control" stream containing meta information, so an Ogg Skeleton file often has three streams: control, audio, and video. The term "Ogg Skeleton" can mean the control stream, or it can mean an Ogg file that contains such a stream.
See Ogg#Identification for identification of Ogg in general. For Ogg Skeleton, ASCII "
fishead" usually or always appears at offset 28.