<dt><code>REQUEST_FILENAME</code></dt>
<dd>The full local filesystem path to the file or
- script matching the request.</dd>
+ script matching the request, if this has already
+ been determined by the server at the time
+ <code>REQUEST_FILENAME</code> is referenced. Otherwise,
+ such as when used in virtual host context, the same
+ value as <code>REQUEST_URI</code>.</dd>
<dt><code>HTTPS</code></dt>
<dt><code>REQUEST_FILENAME</code></dt>
<dd>The full local filesystem path to the file or
- script matching the request.</dd>
+ script matching the request, if this has already
+ been determined by the server at the time
+ <code>REQUEST_FILENAME</code> is referenced. Otherwise,
+ such as when used in virtual host context, the same
+ value as <code>REQUEST_URI</code>.</dd>
<dt><code>HTTPS</code></dt>