Unable to Submit Robot.txt File to GSC robots.txt Tester

[KingKonga]

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.