Socket connection package type question

I have a UR5 CB3 robot with Polysocpe 15. I receive a package from port 30001 that is only 9 bytes long and has a package identifier 5. I see from the Primary/Secondary Client Interface manual there is a 16, 20, and 25. What is a 5?

The value of the nine bytes are 0,0,0,9,5,0,0,0,0