I mean mapping of file extension to filetype is fine as an OS feature. On Unix that's /etc/mime.types (or /usr/share/misc/mime.types, depending on the system),

I mean mapping of file extension to filetype is fine as an OS feature. On Unix that's /etc/mime.types (or /usr/share/misc/mime.types, depending on the system), on Windows that's the registry. What I despise is are tools that vomit random stuff in to your config, whether that's the registry or ~/.config/.