Convert TEXT MARKDOWNPHPEXTRA to 9 (Man Page)

The TEXT file extension, associated with PHP Markdown Extra Documentation, refers to plain text files used to write and store documentation. These files are simple, human-readable, and can be easily converted to HTML using Markdown syntax. The TEXT extension is commonly used for README files, configuration files, and other documentation purposes. Markdown Extra enhances the basic Markdown syntax with additional features like tables, footnotes, and definition lists, making it a powerful tool for creating well-structured documentation.

The 9 file extension refers to Section 9 of the Unix manual pages, specifically covering Kernel Routines. These manual pages provide detailed information on kernel APIs, internal structures, and other essential aspects of kernel development. Developed by Dennis Ritchie and Ken Thompson at AT&T Bell Laboratories in 1971, Section 9 is crucial for kernel developers but is not universally available due to its specialized nature.