Basically, it looks through each of the sub-blocks inside a block at some position. (like the 9 that are there as of now with BLOCK_DIVISOR=3).

Then if any of them are different, it returns null - implying that the block is not full of a single entity.

If the block has one entity taking up the whole thing, it returns what that entity is.

I thought it would be useful for the purpose of checking to see if a person could move into something.  Especially useful if it is a wall or something, although it may be better to have individual methods like isWall(Position) or something for that.