AsciiDoc is a human-readable document format, semantically equivalent to DocBook XML, but using plain text mark-up conventions. AsciiDoc documents can be created using any text editor and read “as-is”, or rendered to HTML or any other format supported by a DocBook tool-chain, i.e., PDF, TeX, Unix manpages, e-books, slide presentations, etc. Common file extensions for AsciiDoc files are adoc and historically txt (as encouraged by AsciiDoc's creator).
The AsciiDoc format is being standardized by the Eclipse Foundation.