I have no idea! The menu is a little basic and bare so maybe it was a debug thing left in by mistake? They spruced up the presentation a lot for the Tekken 3 version

Odd thing was the U.S. Tekken 3 theater mode would let you view T1 and 2 endings if you inserted a copy of those into your PS1. I thought that was insane at the time. Didn't know it was a cut mode from the first two.