dummy out

From Japanese ダミー (damī), which was often used as a placeholder term for the designation of certain things that ended up going unused in a video game. The Japanese term was itself derived from English dummy, and thus tended to be translated in games (even if inaccessible by normal means) as "DUMMY".

ダミー may specifically be a derivative of the programming sense of English dummy.

dummy out (third-person singular simple present dummies out, present participle dummying out, simple past and past participle dummied out)

1. (video games) To remove (a feature, subplot, item, or character) from a video game.