From NirSoft Freeware
FileTypesMan is an alternative to the 'File Types' tab in the 'Folder Options' of Windows. It displays the list of all file extensions and types registered on your computer. For each file type, the following information is displayed: Type Name, Description, MIME Type, Perceived Type, Flags, Browser Flags, and more.
FileTypesMan also allows you to easily edit the properties and flags of each file type, as well as it allows you to add, edit, and remove actions in a file type.
Start Using FileTypesMan
FileTypesMan doesn't require any installation process or additional DLL files. In order to start using it, simply copy the executable file (FileTypesMan.exe) to any folder you like, and run it.
After running it, you should wait a few seconds until the file types list is loaded. If the loading process is too slow, it's recommended to turn off the icons loading (Options->Don't Load Icons in menu), so in the next time that you run FileTypesMan, the loading process will be faster.
The main window of FileTypesMan contains 2 panes. The upper pane displays the list of all extensions/file types registered on your computer. When you select a single file type in the upper pane, the lower pane displays the list of all actions of the selected type.