mdast-util-frontmatter parses and handles frontmatter content in Markdown. It adds frontmatter support to the mdast syntax tree, representing frontmatter as a distinct node. This utility enables the extraction and utilization of data defined within frontmatter blocks (typically YAML, TOML, or JSON) in your Markdown documents. It's crucial for tools that need to process metadata alongside the Markdown content itself, such as static site generators or content management systems.