The requested URL was not found on this server

In my google analytics account, a url with the suffix /b still appears. However, I do not have any test running. And the URL with /b is also not accessible. The error message "The requested URL was not found on this server. But there is traffic on it and I have no idea why. Is this real traffic? And if not, what can I do to keep it out of Analytics?!
Many thanks in advance for your help. Jessica

Bildschirmfoto 2021-10-22 um 09.34.13|690x77