Listed in the USS Enterprise-D's database
John Mason was a notable comedian.
In 2365, Data attempted to create a comedian to help him better understand the concept of "humor". Mason was among the holodeck program files that were contained aboard the USS Enterprise-D, though Data's attempt was ultimately unsuccessful when the computer created a holographic "audience" that was programmed to laugh at literally anything – whether it was actually funny or not. the program list code for this comedian was ZB-45234. (TNG: "The Outrageous Okona")
The comedian was never mentioned in dialog; this name came from a list of comedians.
This character was named after producer John Mason. (Star Trek: The Next Generation Companion)