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http://kmeleon.sourceforge.net/wiki/MacroLanguage2
The K-Meleon Plugins
plugin( PLUGIN, COMMAND ); Since version 0.7
pluginmsg( PLUGIN, COMMAND, ARGS ); Since version 0.7
$REPLY = pluginmsgex( PLUGIN, COMMAND, ARGS, TYPE ); Since version 0.7
Runs a plugin command. The possible values of COMMAND, ARGS and TYPE depend on the specific plugin. See the complete list of plugin commands.