I see a device in my recent security activity:
New sign-in on sdk_gphone64_x86_64 North Carolina, USA · sdk_gphone64_x86_64
I also see it in my list of Google prompts on my 2 factor authentication page. However, I cannot remove it from my list of Google prompts and it doesn't show up in Your Devices.
I suspect this may be a test phone that I created in Android studio, but it's very worrying that it show up in the list of Google prompts on my 2 factor authentication page, but I can't get rid of it.