AI Source Files in Rise

I've been using the AI features for some time and find them extremely useful. However, I'm wondering, when I create a Rise module with my own PDF, Word, and specific Internet links, does the AI pull from anywhere else when creating a course? I've seemed to see material in some of my modules that was not in the sources that I've provided. The material appears to be correct, but there was no mention of some items in the source documents and links. Is AI getting additional material from the web, beyond my sources?