XCAP	XML Configuration Access Protocol
XDI	Xlnt Designs INC
XDS	X/Open Directory Services
XEP	XMPP Extension Protocol
XER	XML Encoding Rules
XFA	XML Forms Architecture
XFF	X-Forwarded-For
XGP	Xerox Graphic Printer
XNS	Xerox Network System
XSD	XML Schema Definition
XSF	XMPP Standards Foundation
XSL	XML Style Language
XUI	XCAP User Identifier