Depends on your interpretation… I would think of it as seeing an infinite bumpy plane 256m thick at the maximum with nothing underneath it (or infinite bedrock if you prefer) and nothing above it (or infinite sky if you prefer) and its not that it would have an “edge” where people suddenly teleport to the other side, but more that the world is just repeating… forever and ever and ever, again and again, seeing the same mountains and same cities, and the same creatures and the same players infinitely many times all moving in lock-step with one another from your point of view 
4608m sorry, typo above. 288 chunks (the odd number is a result of requiring the worlds to be evenly sized at all lods (maximum lod is lod 4, where each chunk is 256m across) which means the worlds have to be multiples of 512m across, but we also have 3x3 tilings of textures for many blocks, which requires the worlds to be multiples of 3 in size as well, which requires them to be multiplies of 1536m across, but we also wanted a 1km draw distance which to prevent issues of trying to see the same chunk in multiple places at the same time, requires at least 2km size, so the minimum world size is then 3072m across going up in multiplies of 1536m, and so we chose 4608m as a “nice” size since 3072 seemed too small.