region.outer.extent length region.outer.extent Specifies the width of the outer side region 0in The region outer extent is the width of the optional text area next to the outer side (opposite the binding side) of the body region. For double-sided output, this side region is fo:region-end on a odd-numbered page, and fo:region-start on an even-numbered page. For single-sided output, this side region is fo:region-end for all pages. This correspondence applies to all languages, both left-to-right and right-to-left writing modes. The default value of this parameter is zero. If you enlarge this extent, be sure to also enlarge the body.margin.outer parameter to make room for its content, otherwise any text in the side region may overlap with the body text. See also region.inner.extent, body.margin.inner, body.margin.outer, side.region.precedence.