Disclaimer: I’m new to ember and don’t actually know the answer to your question, but I found this in the docs, and it seems reasonable:
*AUTOMATIC CREATION OF BINDINGS WITH /^Binding/-NAMED PROPERTIES
You do not usually create Binding objects directly but instead describe bindings in your class or object definition using automatic binding detection.
Properties ending in a Binding suffix will be converted to Ember.Binding instances. The value of this property should be a string representing a path to another object or a custom binding instance created using Binding helpers (see “One Way Bindings”):
This will create a binding from MyApp.someController.title to the value property of your object instance automatically. Now the two values will be kept in sync.
Also, when the docs fail, take a look at the tests. I checked out the ember repo and grepped a few instances.
% ag -l contentBinding
% ag -l controllerBinding