I Can't Submit my URL Property to the Google robots.txt Tester

I’ve been trying to test my robots.txt file in the Google Tester and I’ve followed all the instructions that were laid out on the YouTube video, but there’s a stupid mysterious URL in the field that I’ve never seen (and don’t know where it came from), it won’t disappear, and won’t let me insert MY URL. So, I can’t test my robots.txt file. Here’s a scrnshot of it.