Convert OPML to MDOWN

OPML, or Outline Processor Markup Language, is a file format utilized primarily for outlining data structures. Initially developed in 2000 by UserLand Software, OPML was designed to facilitate the exchange of outline-based information between different software applications. Its uses have expanded over time, notably in organizing RSS feed lists and managing hierarchical data. The OPML file extension denotes XML-based documents that offer simplicity and interoperability in transferring structured information across diverse platforms. In essence, OPML serves as a versatile tool in the realm of data organization and syndication.

The MDOWN file extension stands for "Markdown Documentation". It is used for files written in Markdown, a lightweight markup language with plain-text formatting syntax designed by John Gruber and Aaron Swartz in 2004. MDOWN files are commonly employed in software development to create readable and editable documentation, leveraging Markdown's simplicity for formatting text, lists, code blocks, and links. The historical significance of MDOWN lies in its facilitation of seamless documentation, enhancing clarity and accessibility across various platforms while remaining developer-friendly.