'', 'xhtml1-strict' => '', 'xhtml1-trans' => '', 'xhtml1-frame' => '', 'xhtml-basic11' => '', 'html5' => '', 'html4-strict' => '', 'html4-trans' => '', 'html4-frame' => '', 'mathml1' => '', 'mathml2' => '', 'svg10' => '', 'svg11' => '', 'svg11-basic' => '', 'svg11-tiny' => '', 'xhtml-math-svg-xh' => '', 'xhtml-math-svg-sh' => '', 'xhtml-rdfa-1' => '', 'xhtml-rdfa-2' => '' );