Hi Sarah -- maybe your monitor/browser are like mine -- that symbol is routinely "hidden" beyond a horizontal scrollbar. I always have to slide over to find it.
Hello there, @spowers2 ...
Checking in with you again. We haven't heard back from you since you first posted this question on July 14, 2018. Have you had an opportunity to review the feedback that cholling and I were able to provide? Did either of our responses help to answer your question? Were you able to find the accessibility checker icon on your Rich Content Editor (RCE) toolbar? If you could please come back to this thread to provide an update for us, that would be helpful. Also, if you feel that either of our above responses has helped to answer your question, please click the "Mark Correct" button near our reply for the one you feel is the most "correct" based on your inquiry. For the time being, I am going to mark your question as "Assumed Answered" because we have not heard back from you (but hoping this has been resolved). However, this won't prevent you or others from posting additional questions and/or comments below that are related to this topic. I hope that's alright with you, Sarah. Looking forward to hearing back from you soon.