Testing navigator.mimeTypes for known names can reveal info and increase fingerprinting risk
I gathered a list of MIME Types from IANA and other sources. Then explicitly used each type to check if navigator.mimeTypes[type] === undefined. I found that I could detect quite a few MIME Types in this way. Including some types that are related to specific application programs and/or peripheral devices.
I was testing Tor Browser 5.0.3 for Windows.