<tr><td><code>%{<var>VARNAME</var>}i</code></td>
<td>The contents of <code><var>VARNAME</var>:</code> header line(s)
in the request sent to the server. Changes made by other
- modules (e.g. <module>mod_headers</module>) affect this.
+ modules (e.g. <module>mod_headers</module>) affect this. If you're
+ interested in what the request header was prior to when most
+ modules would have modified it, use <module>mod_setenvif</module>
+ to copy the header into an internal environment variable and log
+ that value with the <code>%{<var>VARNAME</var>}e</code> described
+ above.
</td></tr>
<tr><td><code>%k</code></td>