In case of HTTP status error, the web server might still send useful information about the error. If a server sent content, the content should be displayed to the user. Besides, other browsers display that content.
Created attachment 38991 [details] Patch If the server sends content with the HTTP status code, display the content instead of throwing an error.
Comment on attachment 38991 [details] Patch r=me. I would suggest re-positioning the comments though when landing, by keeping the original comment and moving the new comment you added next to the !m_responseDataSent at the end of that line.
Landed in 48028