Almost Plain Text
From Just Solve the File Format Problem
Almost Plain Text (APT) is a format for documentation files. Some might ask, "How can something be almost plain text? Is that like being slightly pregnant, or like that ghost in the Harry Potter series who's Nearly Headless?"
In fact, Almost Plain Text documents are designed to be entirely readable in plain-text readers and editors, but to have some defined meanings for particular sequences of characters to permit some degree of meaningful markup, much like Markdown or wiki markup.