Explanation:

Three statements that are true regarding event handling in the Salesforce B2B Commerce managed package are:

Salesforce B2B Commerce relies on a central event channel for communication across various Salesforce B2B Commerce Backbone Views and Models called CCRZ.pubSub. This object allows different components to publish or subscribe to events without being coupled with each other. For example, CCRZ.pubSub.trigger(‘cartChange’) will publish an event named cartChange that can be subscribed by any component that needs to react to it.

CCRZ.pubSub defines the following three functions which can be used for event handling: trigger, on, and once. The trigger function is used to publish an event with a name and optional arguments. The on function is used to subscribe to an event with a name and a callback function. The once function is similar to on, but it will only execute the callback function once for each event.

CCRZ.pubSub extends the Backbone.Events JavaScript object. This object provides methods for managing events in Backbone.js, which is a JavaScript framework that provides models, views, collections, and events for building singlepage applications. CCRZ.pubSub inherits all the methods and properties of Backbone.Events and adds some custom ones.

Salesforce References: B2B Commerce and D2C Commerce Developer Guide, Events, PubSub Class