Hi,
I checked with RC2 where files or directories are located in my disk for Ubuntu and Windows.
I can’t tell about OSX since I don’t have it.
Here is a LibreOffice Calc file listing up them.
rc2dir.ods (9.9 KB)
I am appreciate if someone provides the info about OSX

Basically, files are placed
under the /usr/share/kicad/ on Ubuntu,
under the C:\Program Files\KiCad\share\kicad on Windows.
But some files are not located like this rule.
I think it is good to unify these locations across the platforms,
if there is no technical difficulties or issues.
Regards.