a1: CircumcircularArc[P1, (0, 0), Q1]
If you study the GeoGebra commands in this section, you will notice that
γ is purely decorative and is included only to make the unit circle
visible during the construction process. If the unit circle is required
on the right hand side of any command, it is created using
Circle[(0,0),1] command. If the decorative circle γ were used
instead, then the final tool would require the user to input two points
and the circle. In other words, a little extra effort at this stage will
result in a tool that requires two inputs instead of three.