It is a standard outdoor coaxial cable. Perhaps it looks thin because you are mentally scaling to the size of smaller hobby drones.
Edit: The MK30 is 78 pounds, and about 6 feet diameter. Here is an image with a human for scale:
https://dronexl.co/wp-content/uploads/2023/10/Amazon-Prime-A...
The cable was described in the news as thin. It isn't that high off the ground and with or without the drone in view, it looks thin.
Maybe it's an RG6 drop, but it could also be ethernet or a fiber drop. They're all thin wires, though.