The XML Stylesheet Language (XSL) converts structured, XML files into a "human-friendly" representation. The thought underlying this is that, besides for programmers, no one should ever have to read or write XML. Conversions can be done in two steps:

In systems that are Web-based, the first step is more useful — the first step being called XSL Transformations (XSLT) — as XHTML is directly "processed" by browsers.