What is this symbol, showing a wavy line crossed by an arrow?
I don't know whether the EU assigns a special meaning to that symbol but the wavy line means "AC power" and the diagonal arrow means "adjustable" or "variable". So, given this is a wireless switch, that output is the switched hot line. The outer "N" and "L" terminals are the neutral and hot supply connections, respectively, and the inner "N" is the neutral output connection.