Add the sidebar to your mozilla browser:
try it following this link MoinMoinWikiSidebar.xul
click here: AddPage.html
it isn't functional at all here 'cause the content type coming from the server is always text/html but for the xul sidebar to work i need that the xul file has content type application/vnd.mozilla.xul+xml I tried with the content type on the upload form but...nothing...always sent as text/html
That content-type is not stored, I actually don't know why the field was added at all (note that AttachFile is contributed code). And the way stuff is currently stored, it's simply impossible to remember that content-type.
I see...however here with my local wiki it's perfectly functional because I have setup apache to serve the file directly and I have appended to the apache's mime.types file the correct type... You can't see it working here 
but this sample sidebar can easily be customized to any recent (i mean with RSS feed) MoinMoin wiki installation...try it with your own and report the bugs/ features whishlist here! enjoy!:) With a click you can see all the details about a page change and then load the page, the diff page or the history.
mime is only used to determine the correct extension of the file. It's somewhat confusing. on [get] the mimetype is again guessed from the file itself. Could be fixed by storing an extra file with attachment metadata.
see also MozillaSearchPlugin