A branch operation creates a child release that is the clone of the release being branched.
Branching can be performed only on a release. You cannot branch individual objects contained in the release.
When you branch a release, a batch job creates a deep copy of the release. See What Deep Copy Means.
Important: If you do not select the Clone Shared Content check box, referenced content that already exists in the Products cabinet is not cloned. See How Release Management Handles Shared Content.
What Deep Copy Means
A deep copy operation creates copies of most assets in the source release.