http://git.skank.i2p/i2pplus/I2P.Plus/src/commit/fa0ab5f6df26a9cf51e2ea619cdfdd4caaa537fc/apps/i2ptunnel/java/src/net/i2p/i2ptunnel/I2PTunnelConnectClient.java
Firefox sends: // User-Agent: blabla // Proxy-Connection: keep-alive // Host: blabla.i2p // // We could send these (filtered like in HTTPClient) on to the outproxy, // but for now just chomp them all. line = null ; } else { // Add Proxy-Authentication header for next hop (outproxy) if ( usingWWWProxy & & Boolean . parseBoolean ( getTunnel ( ) . getClientOptions ( ) . getProperty ( PROP_OUTPROXY_AUTH ) ) ) { // specific for this proxy String user = getTunnel ( ) . getClientOptions ( ) ....