Browser source code

Is anyone familiar with Firefox (or other Linux browser) source code ? In
the future I would like to modify an existing browser to just go to one
website (there would be no address bar) and be capable of running an
executable from that website (or a script already on the FriendlyARM) that
would send some data out the serial port. You would click (touch) a link on
the web page and that would send a string out the serial port. Any ideas ?

You can use simple qt browser (in examples) and add handling for serial
line. Firefox is so huge and you don't need all his functionality.