It wouldn't open the one file I was trying to view. Stated "Error: Could not parse hexadecimal number (line: 1; column: 25441)." I tried a test document online that uses all the available features of a rtf document. On this file it rendered the basics OK (italics, underlines, bold) but it failed to render several features such as page breaks.

Good idea, but it needs some work.

Not working for me

Great. Please make the content of the rtf-file accessible for other Firefox extensions (as if it would be a normal html website).