XML Declaration in an XSLT File
From MSXML 5.0 SDK
XML Declaration in an XSLT File
An XSLT file is an XML file. Although it is not required, you should use an XML declaration, such as <?xml version="1.0" encoding="UTF-8"?>, at the beginning of the XSLT style sheet. This allows other applications to recognize the data types contained in the file.
See Also
XML Declaration (XML Developer's Guide)