#### 7.2.137 ui-pdf-viewer

`(ui-pdf-viewer VIEWER)`
  Use the executable VIEWER for viewing the PDF-version of the manual when the ``Manual (PDF)`' menu-item is selected in the ``Help`'-menu. If the `(ui-pdf-viewer ...)` command was never executed, then the default is to use the browser stored in the `PDFVIEWER` environment variable. If the environment variable is unset then the default is compile-time dependent.