We call the first five rules above "wiki" formatting rules. The last two rules are the HTML formatting rule.
Paragraphs. Any sequence of one or more blank lines forms a paragraph break. Centered or right-justified paragraphs are not supported by wiki markup, but you can do these things if you need them using HTML.
Bullet Lists. A bullet list item are lines that begin with a single "*" character surrounded on both sides by two or more spaces or by a tab. Only a single level of bullet list is supported by wiki. For tested lists, use HTML.
Enumeration Lists. An enumeration list items are lines that begin with one or more digits optionally followed by a "." and surrounded on both sides by two or more spaces or by a tab. The number is significant and becomes the number shown in the rendered enumeration item. Only a single level of enumeration list is supported by wiki. For nested enumerations or for enumerations that count using letters or roman numerials, use HTML.
Indented Paragraphs. Any paragraph that begins with two or more spaces or a tab and which is not a bullet or enumeration list item is rendered indented. Only a single level of indentation is supported by
Hyperlinks. Text within square brackets ("[...]") becomes a hyperlink. The target can be a wiki page name, the UUID of a check-in or ticket, the name of an image, or a URL. By default, the target is displayed as the text of the hyperlink. But you can specify alternative text after the target name separated by a "|" character.
HTML. The following standard HTML elements may be used: <a> <address> <b> <big> <blockquote> <br> <center> <cite> <code> <dd> <dfn> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr> <img> <i> <kbd> <li> <nobr> <ol> <p> <pre> <s> <samp> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul> <var>. In addition, there are two non-standard elements available: <verbatim> and <nowiki>. No other elements are allowed. All attributes are checked and only a few benign attributes are allowed on each element. In particular, any attributes that specify javascript or CSS are elided.
Special Markup. The <verbatim> tag disables all wiki and HTML markup up through the next </verbatim>. The <nowiki> tag disables all wiki formatting rules through the matching </nowiki> element.