This node is used to create an arbitrary list of a specific data type. A new element can be added with the New Input button. A new element can also be added by plugging it into the transparent socket. If the list type is Object and no inputs are present, an operator From Selection will be available that adds the currently selected objects as inputs. See examples.
A warning will pop up when you use the Remove Unlinked Inputs button in the node, while if you used the the Remove Unlinked Inputs button in the Advanced Node Settings the inputs will be removed without a warning.