Ich glaube der Hintergrund dieser zusammenfassenden Beschreibung waren so Textstellen wie, Threats S. 54:
In the fall of 2051, Ehran the Scribe, High Prince of Tir Tairngire, gave a speech to the Young Elven Technologists. Ehran intended the contents of the speech to remain "an elven secret," but person or persons unknown leaked it on the Matrix. It's been circulating through various channels ever since, protected from Tir Tairngire's search-and-destroy deckers.
Wobei das wohl erstmal nur heißt, dass es in der Schattenmatrix rumging. Besser unterfüttert wird es durch Loose Alliances S. 75:
In the years since the Awakening, we've uncovered growing evidence that we really don't know as much as we thought we did. Plenty of people have speculated about the cycles of mana, the Mayan calendar and the origins of complex languages like Sperethiel and Or'zet. According to the popular (though unproven) hypothesis, we are currently on the rising arc of a recurrent cycle of magic—the "Sixth World"—that the world has undergone at least twice before. Much of this theory originates in the pseudo-science of authors like Ehran the Scribe, whose ties to the Tir government and the DIMR should be enough to make his opinions at least suspect.
Es gibt auch die Gnome von Zürich-Verschwörungstheorie, die für eine popkulturelle Verbreitung der Vorstellungen spricht.
Der Grund dafür auch sehr einfach: Dunkelzahn. Wieder Loose Alliances ebd:
On the other hand, we are confronted with dragons—if we're willing to trust them—who claim to have Awakened from a long slumber since the last age of magic. Dunkelzahn made numerous comments in public and private regarding "an earlier age," and if you believe the rumors several of the other great dragons have done the same. Nevertheless, the dragons have refused to answer direct questions on the matter (at least in public), and seem to share a common opinion that metahumans just have to figure out their history by themselves.