Although Mania's method is effective, it does result in quirks such as this:

Sonic Mania uses a much simpler approach: it uses a large hitbox based on a given size determined per-entity, and if the player is touching that hitbox while grounded, the collapse is activated.

In early versions of the game, there's evidence that a file named "CLedgeMask.bin" once existed. This may have been used for the top offsets in the proof-of-concept phase of development, back before tables were implemented in the scripting language the game uses.

Well, these ledges are objects, and RSDK doesn't support hitboxes that are angled or any shape other than a straight rectangle. Rather than make a ton of hitboxes to match the ledge's shape, the devs made one hitbox and used a table and checks to determine the top's offset.

If we enable the RSDKv4 decompilation's object hitbox visualizer, we can see that the top of the hitbox for the ledges get taller or shorter depending on where the player is standing on it, rather than having a hitbox that properly matches the ledge itself. What's going on here?