@@ -809,7 +809,8 @@ General writer options
809809: Set the request header *NAME* to the value *VAL* when making
810810 HTTP requests (for example, when a URL is given on the
811811 command line, or when resources used in a document must be
812− downloaded).
812+ downloaded). If you're behind a proxy, you also need to set
813+ the environment variable `http_proxy` to `http://...`.
813814
814815Options affecting specific writers
815816----------------------------------