After the cancellation of the original Battlestar Galactica, Universal re-edited the episodes into two-hour movies and offered them to independent stations as a syndication package.
At least one of these, the "Experiment In Terra" telefilm, included a prologue that showed American astronauts discovering the Battlestar Galactica's log book floating in space. Within it, Adama details the origins of the Cylon race as reptilians who were ultimately conquered by their own cybernetic creations.
Since those telefilms were not released on home video, nor aired anywhere that I ever lived, I never saw this footage until today. Check it out!