It appears that there is no way to tell mozilla to display documents of type
text/* (other than text/plain) to display right in the browser window. I would
like to browse source code files (text/x-java, for example) right in the browser,
but instead I am presented with an open-using/save panel. Neither of these two
options is the desired choice. I could not find a way to tell mozilla to treat
text/x-java the same way it treats text/plain.