"Universal Edit Button" for marking web pages as editable

There exists an intresting suggestion for a Universal Edit Button on web pages. Basically, just as the RSS icon pops up in the browser address bar when visiting a page with a feed related to it, an edit icon shows up when visiting an editable page.

Marking the page as editable is done by adding a <link/> element with content as follows:

<link rel="alternate" type="application/wiki" title="Edit this page!" href="wiki?edit=WelcomeVisitors"/>

The values of the rel and type attributes are currently a bit strange and are being discussed.

Apparently, Wikipedia has already adopted it and there is a Firefox extension available to watch it live.