Canto for Midale on that village in Ch1-1 displays the pathfinding for the entire map. She can only move her normal movement, but moving the cursor beyond the customary 11 tiles crashes the game.
Edit: It's somehow broken the pathfinding display for all of my units now, and it's saved to the save file. Was fixed by restarting the chapter. Save with bug active - no$gba format.
Edit 2: Seems it can be triggered from the other village as well. Doesn't require Canto, just visiting one of the villages will trigger it.