Unable to add override - Error in port specification

I’m attempting to add an override. When I try save, it says “Error in port specification”. There’s no option for port from what I can see:

Am I missing something?

You should check the documentation about Creating Overrides since it will clarify the purpose of the Location field and tell you what to enter there. “package” is not a valid entry.

The Location field must be a port number followed by the intended Transport Layer protocol specification (either TCP or UDP).