Clipboard Format List Tool (CFList) is a free utility that provides information about the formats currently available on the Windows clipboard.
Use of this tool is very simple. The ListBox on the left-hand side (see screenshot below) displays a list of the formats currently held by the clipboard. There is a Refresh button to update the list if the clipboard contents have changed. By clicking on an item in the list, information about the format is displayed on the right-hand side, including the integer value that identifies this format to the operating system.