# File lib/asciidoctor/converter.rb, line 76
      def setup_backend_info
        raise ::ArgumentError, %(Cannot determine backend for converter: #{self.class}) unless @backend
        base = @backend.sub TrailingDigitsRx, ''
        if (ext = DEFAULT_EXTENSIONS[base])
          type = ext[1..-1]
        else
          # QUESTION should we be forcing the basebackend to html if unknown?
          base = 'html'
          ext = '.html'
          type = 'html'
          syntax = 'html'
        end
        {
          'basebackend' => base,
          'outfilesuffix' => ext,
          'filetype' => type,
          'htmlsyntax' => syntax
        }
      end