⁺ - Duplicate
The resulting link's arity is the same as the consumed link's arity. Note that the arity refers to that of the resulting link, not the number of links this quick consumes.
Duplicate the previous link. Does not combine them together, so
F⁺€ will call
F and then
F on each, not
FF on each.
<link>⁺- push another copy of the link