The "bs" macro is used to escape characters with a backslash. In wiki markup, the backslash (\ ) is often interpreted by Confluence directly and thus may not display in the final markup. The "bs" macro fixes this.
The first unnamed parameter is the text to backslash. If omitted, the macro will render a double backslash instead.
The named parameter "tt" can be set to false to cause the text to display in the current font rather than a monospace font.