code: public static String getFromMimeType (String mimeType, Supplier<String> notFound) {
          mimeType = mimeType.toLowerCase ();
          return mimeTypeRemappings.containsKey (mimeType) ? mimeTypeRemappings.get (mimeType) : notFound.get ();
      }
docs: Returns a mime type with a known format reader from the given mime type. Some MIME types are
  application or vendor specific examples that use a standard underlying format, like XML.
  There are also examples of synonym types, like "text/csv" and "application/csv" that we want
  to support.