The media type mappings in catalina/src/conf/web.xml could be brought more in sync with the Apache HTTP Server mime.types file. In particular the XHTML media type is wrong (it should be "application/xhtml+xml", not "application/xhtml"), and it'd be better to associate the .xml file extension with "application/xml" rather than "text/xml". Thank you.
Created attachment 13452 [details] Diff to update web.xml media types
Done for Tomcat 5.0.30.
Done also for 5.5.5. Thanks for submitting the patch ;)