libxml is a library (hence lib) of tools that let you work with parser functions in PHP. The newest version, called libxml2, was introduced at the beginning of 2019. In this article, we will review its main functions. While PHP libxml extension is free to download and use, it does not come inbuilt in PHP. It means that you won't be able to use any of the functions without the required extension.
PHP libxml: Main Tips
PHP libxml functions and constants are meant for parsing XML documents. They should be used combined with functions associated with DOM, XSLT, and SimpleXML. To use these functions, you must download the libxml2 package from the official website.