What rocket use for mime type determination

How does rocket find the mime type of a file ? Apparently it does not use the file unix command… so what ?
I have to add some unrecognised file type to the allowed files to be uploaded.
Thanks in advance…

Found it it’s a json file that make a link from file extension to mime-type… well…

Hi FredGoud,

I was also looking for this. Can you tell me the path to that JSON file?

Thank you in advance.