No one wants to waste time clicking into every page of a tree to figure out what DocType it uses, what templates it allows, or when it was last edited. DocType Inspection takes away all the pain of this by adding a handly little navigation section above the menu dialogs - just right click a piece of content and get some basic information about the page!
Want to see it in action? There's an animated gif below that shows it working :)
Should work on all versions of Umbraco 7.