The Developers Chest is in Rust Commons West and is outside the map. It is not hard to get to, but you have to die to get out.
The normal red chest got it's name from people thinking the developers made that chest and it was their favorite, that isn't exactly true.
Really it is just like the hidden chest in Promotory. this one doesn't spawn a certain weapon either.
So, if you want to get the chest go ahead nobody is stopping you plus you can feel special for knowing where it is.