There is only one file type that uses the .XFDL extension:
Extensible Forms Description Language (XFDL) file that uses XML to describe a structured, legally-binding business form; contains business form data including layout, business transaction details, inline mathematical and conditional expressions, and digital signatures; addresses business transaction needs for non-repudiation, auditability, security, and preservation of context.
XFDL files were designed to create standardized and interchangeable business forms. They were adapted from the Universal Forms Description Language (UDFL) to include the XML format. They are used in business and government e-Commerce transactions.
NOTE: IBM acquired PureEdge Solutions, the developer of the PureEdge Viewer program. The United States Airforce has discontinued the use of the PureEdge Viewer software. You should use the Lotus Forms Viewer instead.
Updated: July 4, 2010