XSLT (Extensible Stylesheet Language Transformations) is a language for transforming XML documents into other XML documents, or other formats such as HTML, plain text, or even XSL-FO (XML Formatting Objects). It works by applying a set of template rules to the input XML document. Each template rule specifies how to transform a particular element or attribute in the XML document. The XSLT processor reads the input XML document and the XSLT stylesheet, and then applies the template rules to the XML document to produce the output document. XSLT is often used for tasks such as converting XML data into HTML for display on a web page, generating reports from XML data, or transforming XML data into a different XML schema. It's a powerful tool for manipulating and transforming XML data, enabling developers to easily convert data between different formats and structures. XSLT is a declarative language, meaning that you specify what you want to achieve, rather than how to achieve it. This makes XSLT stylesheets relatively easy to read and maintain.