Please consider registering media types to the Internet Assigned Numbers Authority (IANA) before requiring their inclusion in /etc/mime.types. https://www.iana.org/form/media-types Simplified registration procedures for vendor and personal trees have been implemented since RFC 6838, that states: "it should rarely, if ever, be necessary to use unregistered types." https://tools.ietf.org/html/rfc6838 I have confirmed that the process is fairly quick and painless by registering various media types in 2012, 2014 and 2020. -- Charles Plessy