Xmf\Metagen is a metadata generator class. It can assist in analysing arbitrary text, and extracting useful subsets, such as the most common words, or summary paragraphs.
Metadata is defined as "data that provides information about other data." In a web application context, this can refer to HTML meta tags, which are data which describe a page's content. Metadata can also be indexing and tagging data related to application data or content.
While it is usually best to provide tools for content authors to specify custom metadata, automated extraction of metadata can be a useful tool.