XML Prolog and instructions
Every XML file starts with the prolog, giving information about the document. The minimal prolog identifies it as an xml document <? version=“1.0”?>
The prolog may also include the encoding and whether it is a standalone document: <?xml version="1.0" encoding="ISO-8859-1” standalone="yes"?>
If it is not standalone, it may specifiy external “entities” which may be named in the document or an external DTD
An XML file may also contain processing instructions for the application processing the document: <?target instructions?> where target is the name of the application.