Maximum length of a MIME Content-Type header field?

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I hope I havn’t misread, but it looks like the length is max 127/127 or 255 total.

RFC 4288 has a reference in 4.2 (page 6):

Type and subtype names MUST conform to the following ABNF:

   type-name = reg-name
   subtype-name = reg-name

   reg-name = 1*127reg-name-chars
   reg-name-chars = ALPHA / DIGIT / "!"https://stackoverflow.com/"#"https://stackoverflow.com/"$"https://stackoverflow.com/"&"https://stackoverflow.com/"."https://stackoverflow.com/"+"https://stackoverflow.com/"-"https://stackoverflow.com/"^"https://stackoverflow.com/"_"

It is not clear to me if the +suffix can add past the 127, but it appears not.

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