Download – Edit – Upload…

This editor loads the ini file given by a MediaWiki’s external edit link. It then starts the default application registered for the document which is defined inside the ini file. After editing the document you can preview the changes to the MediaWiki and/or upload the final version.

You can get the tool at Sourceforge.

Here are some screenshots:

downloading-the-document ready-to-edit user-password-dialog

And a video on Vimeo of how this works: