While working on the Wikipedia Zoom and Pan tool (Issue 291) I found an
unusual edge condition where the svgObject.contentDocument.rootElement
property was not getting set after I deployed my file to my remote web
server. It turns out that the MIME type was text/xml rather than
image/svg+xml, which queued some bugs in FF/Native. Making the MIME type
correct fixes this edge condition. Update the config.html testing tool and
the docs to inform users to set this mime type.