Is there any way for those of us with average intelligence to contribute to tools like this? I know I'm a decent developer, but I feel entirely entirely inadequate to participate in this enormous, scary world of AI.
The people doing this aren't magical geniuses; they've just put the time and work into the subject and have been able to get themselves into a position they can do this all day surrounded by others they can collaborate with.
As with most human endeavors, the trick is to just get started, and not get frustrated and give up when it turns out you don't know anything at first. Some people don't mind starting with a ton of abstract learning about the subject, others prefer trying to accomplish specific tasks, learning the theory along the way.
For your specific question, as with all software, there's likely a lot to be done that has little to do with the main task of the tool and is just the everyday tasks of ease of use, interoperation with other tools, testing, etc. If on the other hand you want to get into the scary world of AI, like many others I'd recommend the Coursera machine learning course as a great place to start[1]