Apple and MS both tried to hide file associations from users when you are looking at directories. I can’t tell you the number of times this has brought disasters. For example, today in one directory I found two files called 99er13; one is an HTML page; another is an XHTML page. So what the heck is that supposed to mean?
After dropping into command line, I see that the xhtml file has an .xhtml suffix. (I don’t know why I did that). Maybe if you were viewing directories through File Explorer, you’d be able to tell by glancing at the file type in the middle column. But what if you were at the Save As dialog or Open File dialog? Neither dialog provides this file type information; instead you are presented with two identically named files. Bad, Microsoft, bad!