With the markup language XML, InDesign enables a strict separation of layout and text. A particularly powerful XML feature in InDesign is the ability to assign previously imported or InDesign-created XML tags to predefined formats such as paragraph styles, character styles, and table styles. This makes it possible to populate entire layout templates with fully formatted content in a very short time. During an XML import, an Extensible Stylesheet Language Transformation (XSLT) file specifies, among other things, the order in which the XML elements should be sorted if the order of the tags in InDesign differs from that of the XML elements. To check for occurrences of specific elements, attributes, and entities in an XML file, Document Type Definition (DTD) files are used. These thus define the expected XML structure of an XML file. Another XML-related InDesign feature is the so-called InDesign Markup Language (IDML), a markup language introduced by Adobe to describe entire InDesign documents in XML format. In theory, this makes it possible to edit or even create an entire InDesign document using XML. Based on IDML are the so-called InDesign snippets in the IDMS file format. A snippet is an XML file that describes an InDesign asset. Any InDesign asset can be exported as a snippet. Likewise, snippets can be imported into an InDesign document and edited as desired.