When a function passes ownership of a reference on to its caller, the caller is said to receive a new reference. When no ownership is transferred, the caller is said to borrow the reference.
Nothing needs to be done for a borrowed reference.
However, in practice, you will rarely use these ways of creating and populating a tuple or list. While passing a reference to most functions does not change your ownership responsibilities for that reference, many functions that return a referece to an object give you ownership of the reference.