The Inter Application Communication library is found in 01eXoResources.war:/javascript/eXo/core/Topic.js

/**
 * publish is used to publish an event to the other subscribers to the given channels
 * @param {Object} senderId is a string that identify the sender
 * @param {String} topic is the topic that the message will be published
 * @param {Object} message is the message that's going to be delivered to the subscribers to the topic
 */
Topic.prototype.publish = function(/*Object*/ senderId, /*String*/ topicName, /*Object*/ message ) { ... }

/**
 * isSubscribed is used to check if a function receive the events from a topic
 * @param {String} topic The topic.
 * @param {Function} func is the name of the function of obj to call when a message is received on the topic
 */
Topic.prototype.isSubscribed = function(/*String*/ topic, /*Function*/ func) { ... }

/**
 * subscribe is used to subscribe a callback to a topic
 * @param {String} topic is the topic that will be listened
 * @param {Function} func is the name of the function of obj to call when a message is received on the topic
 * 
 * func is a function that take a Object in parameter. the event received have this format:
 * {senderId:senderId, message:message, topic: topic}
 *
 */
Topic.prototype.subscribe = function(/*String*/ topic, /*Function*/ func) { ... }

/**
 * unsubscribe is used to unsubscribe a callback to a topic
 * @param {String} topic is the topic
 * @param {Object} id is the id of the listener we want to unsubscribe
 */
Topic.prototype.unsubscribe = function(/*String*/ topic, /*Object*/ id) { ... }

Topic.prototype.initCometdBridge = function() { ... }