expand on ProxyPassReverse args

    match the proxy, you must load and enable <module>mod_proxy_html</module>.

    </p>

    <p><var>path</var> is the name of a local virtual path; <var>url</var> is a

    partial URL for the remote server. These parameters are used the same way as

    for the <directive module="mod_proxy">ProxyPass</directive> directive.</p>

    <p><var>path</var> is the name of a local virtual path. It is combined 

    with the requests scheme, host, and port to form the replacement 

    prefix of the affected response header.  

    This parameter is usually the same as the first parameter of the 

    <directive module="mod_proxy">ProxyPass</directive> directive.

    </p>

    <p><var>url</var> is a partial URL for the remote server. When the remote

    server sends the specifically mentioned headers beginning with this partial

    URL, the prefix from the remote server is replaced with a prefix that

    points to the reverse proxy.

    This parameter is usually the same as the second parameter of the 

    <directive module="mod_proxy">ProxyPass</directive> directive, but it may

    differ if the remote server uses a different scheme, host, port, or path

    in the affected headers.  In configurations with 

    <directive module="mod_proxy">ProxyPreserveHost</directive>, the hostname

    in the partial URL may already be the hostname of the reverse proxy, which

    will prevent the matching and replacement done by this directive.

    </p>

    <p>For example, suppose the local server has address

    <code>http://example.com/</code>; then</p>