wp-block-markup

WordPress Gutenberg block markup uses specific comment delimiters to define block boundaries and JSON to store block attributes. This structure allows the editor to parse, validate, and reconstruct nested or self-closing blocks from raw post_content.

Block attributes in WordPress are serialized in HTML comment delimiters as JSON. The save() method defines how these attributes are reconstructed and rendered in the final HTML output, ensuring the block remains stable and valid.

The 'Block contains unexpected content' error occurs when the saved HTML does not match the expected block markup generated by the save() method. Validating the block delimiters, attribute serialization, and nesting rules helps debug and resolve this discrepancy.

The three forms of WordPress Gutenberg blocks are balanced, self-closing, and nested blocks. Each form follows specific delimiter conventions and nesting rules to ensure proper parsing and serialization within the post_content structure.

Yes, HTML tags are used directly inside WordPress block delimiters for the rendered output, while block attributes are stored separately in JSON comments. Understanding this mapping is crucial for debugging post_content and building valid templates.