'Hide' is indeed the expression, which implies that it remains attached. Try to change the extension in OS X, or append one when it seems that there is not one present, and you will quickly get a stern upbraid from Finder, and a prediction of dire consequences if you do not mend your ways forthwith.
One has to suspect that OS X Finder does add extensions by default. Your choice is only whether you choose to show them or not. If you have the will and the stamina, this may provide light, or obscurity, according to your taste.
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