Charlemagne had no secrets from Alfheim.
Everything about Alfheim was a secret to Charlemagne.
The above two sentences are not exaggerated at all. Charlemagne was completely transparent to Alfheim in one direction. The gap between the two in terms of the organization, personnel quality, technical means, and fund allocation of their intelligence agencies was so huge that it was essentially unbridgeable. After the frenzy of universal speculation and corruption spread, the few cards Charlemagne held in their hand were seen through cleanly by their opponents.
Roland's guess had once again hit the bull's-eye, the Wehrmacht knew more about the defenses from Sedan to the Meuse River area than Charlemagne himself.