I would guess, as the only video I can verify on the ILs is the diner's Lv. 16, that Lv. 1 is the train level. You can also 100% the tutorial level, which does make me curious about if it should be added or not.

moderation was recently changed, I was not sure about this myself for quite some time. We will have to discuss in the discord and decide there. I recommend joining if you're not already in it.