Files in /dev below devtmpfs mount

I mentioned on some Linux systems, that there are actual files on the root partition in /dev in unmounted state. These will be covered by the devtmpfs mount once established, which usually happens quite early eg. when the inital ramdisk remounts anything to the root partition.

So the files will never be accessed I guess.

Is this an artefact left by the distributors, or is there any reason for those device files?