The MathML Libraries is mainly not a Java project. It contains several useful strings to work with MathML. For example, valid headers, doctypes, a list of valid MathML 3.0 content tags and so on. Furthermore, we stored all used XPath strings also. The libraries are represented as YAML files. You can use these libraries to work with content MathML in other programming languages. If you want to use the libraries in a Java project, we also provide simple pojo projects to access and use the XPath strings.