This handler gives allows for an opportunity to translate the URI into
an actual filename, before the server's default rules (Alias
directives and the like) are followed.
Note:
At the time when this phase of the request is being processed, the
URI has not been translated into a path name, therefore this
directive will never be executed by Apache if specified within
<Directory>, <Location>, <File> directives or
in an .htaccess file. The only place this can be specified is
the main configuration file, and the code for it will execute in the
main interpreter.