Convert OPML to 4 (Man Page)

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 4 file extension refers to Unix Section 4 Manual Pages, which document special files and device drivers. These files, such as "mouse.4", describe how devices interact with the Unix operating system and are accessed using the "man" utility. Historically, these manual pages have been a fundamental part of Unix documentation, helping users understand and manage system devices.