Matching the Default File
You can match the default file within a single directory using a special value for the filename match. The syntax is:
<match:filename value="No File Specified"> </match:filename>
"No File Specified" is a literal string used as the match value, because it is unlikely anyone would have an existing file with this name. This value instructs the edge server to apply metadata to whatever file the origin server would deliver as the default if the directory were accessed without specifying a file. This is handy because not all default files are .html.