Created attachment 45910 [details] screenshot Yellow looks like warning color to me, but there is nothing wrong with 304 Not Modified responses.
Created attachment 82304 [details] [PATCH] Suggested fix
Comment on attachment 82304 [details] [PATCH] Suggested fix Clearing flags on attachment: 82304 Committed r78486: <http://trac.webkit.org/changeset/78486>
All reviewed patches have been landed. Closing bug.