[mborch]

Since any argument after one or more "**" must be a keyword-argument, perhaps f(pos_a, pos_b, **kwargs, kw_a, kw_b, ...) or even f(pos_a, pos_b, **, kw_a, kw_b, ...).

This would make the proposal's first example read:

    my_function(**, my_first_variable, my_second_variable, my_third_variable)

More readable IMHO. They do mention f(a, b, *, x) in the proposal and present some objections, but arguably ** makes it easy to understand that these are keyword arguments.