Where is the initialize function for Backbone.Model documented?

I'm looking up how to instantiate a Backbone.Model. Under the [docs for constructor / initialize](http://backbonejs.org/#Model-constructor), it says:

> When creating an instance of a model, you can pass in the initial values of the attributes, which will be set on the model. If you define an initialize function, it will be invoked when the model is created.

What it doesn't say is what arguments that initialize function takes, which if I remember correctly includes the `options` object passed in on instantiation.

Where is this documented?

Review the linked Backbone.Model constructor/initialize documentation first. Clarify which arguments initialize receives, including whether the options object passed during instantiation is included; done when the documentation answers how initialize is called.

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