What are the rules for writing XML?

<?xml version="1.0" encoding="UTF-8"?>
<!-- XML prolog with version and encoding is required -->
<root>
    <!-- There must be exactly one root element -->
    <element attribute="value">
        <!-- Element and attribute names are case-sensitive -->
        Element content
        <!-- All opening tags must have corresponding closing tags -->
    </element>
    <empty_element/>
    <!-- Empty elements can be closed with a single tag with a slash -->
</root>

• Case sensitivity: XML tags and attribute names are case-sensitive.
• Root element: The document must have exactly one root element.
• Paired tags: All opening tags must have matching closing tags. Empty elements can use the <tag/> syntax.
• Attributes: Attribute values must always be enclosed in quotes (single or double).
• Nesting: Elements must be properly nested.
• Names: Element and attribute names cannot start with a number or the xml (any case) prefix, cannot contain spaces or : characters.
• Special characters: Special characters (<, >, &, ', ") must be replaced with their entities (<, >, &, ', ").
• Comments: Comments are formatted as <!-- comment -->.
• Prolog: Including an XML prolog (e.g., <?xml version="1.0" encoding="UTF-8"?>) is recommended.
• Whitespace: Whitespace characters (spaces, tabs, newlines) between elements are generally ignored by the parser unless specified otherwise.