There is a group of config options in the local.config.php file
# Options for the signature that's generated
Config::Set('SIGNATURE_TEXT_COLOR', '#000000');
Config::Set('SIGNATURE_USE_CUSTOM_FONT', true);
Config::Set('SIGNATURE_FONT_PATH', SITE_ROOT.'/lib/fonts/MankSans.ttf');
Config::Set('SIGNATURE_FONT_SIZE', '11');
Config::Set('SIGNATURE_X_OFFSET', '10');
Config::Set('SIGNATURE_Y_OFFSET', '17');
Config::Set('SIGNATURE_FONT_PADDING', 4);
Config::Set('SIGNATURE_SHOW_EARNINGS', false);
Config::Set('SIGNATURE_SHOW_RANK_IMAGE', true);
Config::Set('SIGNATURE_SHOW_COPYRIGHT', true);