These are the file types discussed here whose filenames can include path information: the source file given on the command line (wgml/source) an option file given on the command line (wgml/opt) a layout file given on the command line (wgml/lay) a source file named in an :IMBED block (wgml/imbed) a source file named in an :INCLUDE block (wgml/include) a source file named in an .AP block (wgml/.ap)