Actually, it's not a leap because it's neither upwards or forwards.

The orbit is already ahead of our count so we add a day is moving us backwards along the orbital count.

If we removed a day then that missing day would be a leap day as we leap over it to the next day in the calendar.

So really this is the non-leap since we're counting it, it's all the other years that don't have a 29th that are leap years because we're leaping over the 29th day of February.