With ShellExView you will be able to know exactly how some extensions work or what they are for. What's more, with this free tool you can see all the properties, obtaining very complete information about the extension that you have selected. It is even possible to learn the CLSID code, and various of the attributes of the file that forms the extension. What's more, in case you need it, all the reports can be exported in HTML format.
What's more, in the case that you are very brave, you can open the Windows Registry with RegEdit with the extension of your choice, perfectly identified and selected to edit it directly.