Extensible Markup Language (XML) is a generic markup language that was developed and standardized by the W3C®. It is a simplified form of the older SGML that enables the easy creation of specific markup languages (applications) for different purposes and different types of data. It is used for data serialization, for which it has several competitors such as JSON or YAML. XML processing is supported by a number of tools and programming languages. XML is primarily focused on data exchange between applications and published documents. It is used to describe the structure of the individual parts of a document and is not concerned with appearance, which can be defined via CSS. Another processing function of XML is the transformation of one document type into another, or into other XML applications. XML tags are used in a document to organize the hierarchy of individual parts of the text. As such, XML documents contain more information than documents that are simply tagged for appearance; (e.g., fonts, colors, paragraph attributes, etc.) In short, XML documents are richer in information.