What is XSL-FO?

XSL-FO (Extensible Stylesheet Language Formatting Objects) is a markup language for specifying the formatting semantics of XML documents. It's most often used to generate printable documents, such as PDFs, from XML data. XSL-FO provides a vocabulary of formatting objects that describe how the content should be laid out on pages, including elements for paragraphs, lists, tables, and graphics. XSLT is typically used to transform XML data into XSL-FO, which is then processed by an XSL-FO processor to produce the final formatted output.