MaRTE OS tutorials try to follow the Linux Documentation Project (LDP) guidelines. We use an useful mark-up language for software documents called Docbook. Docbook is similar to HTML, but it has its own tags. For example, there is a tag for listing code, etc. You can get a complete list of usable tags from [1]. The Docbook language has been defined by two meta-languages (SGML and XML). We prefer, as LDP, the XML flavour. The language is defined in a file called DTD (Document Type Definition). See http://docbook.org/xml/4.2/docbookx.dtd
By now, we could write a file example.xml using the docbook tags and check if our file conform to DTD rules. But apart from this we don't have anything, just a mix of tags and text. We need another file for mapping those tags into HTML, TXT, PDF, etc. There are two alternatives for that: DSSSL and XLS. We prefer to use DSSSL (Document Style Semantics and Specification Language).
To sum up, we are going to create Tutorials using a Mark-up language called Docbook-XML. You can look up the tags of the language in [1]. Once you have your tutorial in a file (i.e. example.xml) you will need to apply a script in order to convert that file into HTML, TXT, PDF... with some style.