File names should be lowercase?
- 
I can observe that Qt sources, KDE projects, uses lowercase for file names. Why? Upper and lower case is not problem for case sensitive filesystems., but also Windows preserves case. Maybe problem is in case insensitive systems when two file names is distinguish only in case? File names with capital letters are more readable by human, usually file names are class names, which area two or more words joined together. .
 - 
Hi,
The reason is likely lost in the sands of time but in any case, the user facing headers naming follows the class name.
On a side note, macOS uses case insensitive by default for their filesystem.
 - 
Qt case sensitive headers are short and includes appropriate lowercase headers. This case sensitive headers are created by installer? How installer knows this filename for lowercase include?