Is this icon included as part of the Cocoa API? What is the icon name?

[![Sidebar icon that is shown for applications such as photos and safari](https://i.stack.imgur.com/lmu5m.png)](https://i.stack.imgur.com/lmu5m.png)

I read the HIG but could not find a reference - <https://developer.apple.com/library/mac/documentation/UserExperience/Conceptual/OSXHIGuidelines/SystemProvided.html#//apple_ref/doc/uid/20000957-CH92-SW1>