PDF 1.7 supports a limited number of standard tags, limited enough that I can freely list them here: Document, Part, Article, Section, Division, Block quotation, Caption, Table of Contents (TOC), TOC item, Index, Paragraph, Heading, six hierarchical Heading levels, List, List item, List item body, Label, Table, Table row, Table header cell, Table data cell, Table header row group, Table body row group, Table footer row group, Span, Quotation, Note, Reference, Bibliography entry, Code, Link, Annotation, Figure, Formula, and Form.