Vernor Vinge said this quote

“ Here and there amidst the wreckage, she found advanced devices that more or less still functioned. With one exception, she’d revealed these to Johanna and then to Woodcarver, and—after it was founded—to the Executive Council. Ravna had kept her mouth shut about the surveillance suite; she and the Children were trapped on a world of medieval strangers....So at the beginning Ravna had kept some secrets. It was now years too late to reveal this one. In the Beyond, “cameras” were more than what early tech civilizations imagined. Cameras could be a coat of paint, or critters that looked like insects, or even a bacterial infection. Delivery of the information to the observer could be even stranger, a diffuse cloud of perturbations—acoustic, visual, thermal—that took enormous processing to reconstruct. ”