I've noticed that I have to account for differences in capitalization of file extensions of the same type. For example, some part files are ".sldprt" while most of them are ".SLDPRT". Why is this?

My initial impression is that .sldprt files are not linked to a drawing, while .SLDPRT files are linked to a drawing. I could be totally wrong though, this is just what I saw as a likely possibility.

If anyone has more examples of file extension capitalization inconsistency, please share! I'm a bit curious.