A 'clone' node is an exact copy of a node. It is not a transclusion and it does not keep a reference to the node that it was copied from.
To create a clone of a node, first select the node you want to clone, open its right-click menu and then select the 'Clone' menu item, (see figure 1).
A new clone node will appear to the south-east of the original node, (see figure 2 below).
N.B. Unlike Shortcuts, clones of views are real views, (as in the example in figure 2. showing a clone of a map). They can contain other nodes and links. But clones made of maps and lists do not currently have their contents copied, (i.e. the nodes and/or links that the original may have contained).