So I just gathered and organized all of my Atari 2600 game manuals (at least, those I know of–there are probably a bunch floating around in stray boxes here and there), and I discovered something.
Back in the day, Game Program was a trademark of Atari.
Check it out.
Here’s the manual for Defender, which says it is the Atari® Game Program™.
Here is a catalog saying that there are 45 Game Program™ cartridges.
Ergo, Game Program is a registered trademark of whoever holds the Atari intellectual property these days.
So watch yourselves.