How is a "gun platform" defined?

[Spartan198]

I was looking at the R2B: Return to Base page and it lists numerous aircraft, helicopters, and ships as "gun platforms", even ones that don't carry any IMFDb-approved armament (like the B-2 stealth bomber) or don't appear to have any onboard weapons at all (a helicopter carrier).

Furthermore, the author just simply identifies the platform (e.g., an F-15 fighter) instead of identifying the actual gun on said gun platform.

Is there a defined standard here as to what constitutes a gun platform other than "it has a weapon on it"?