docs: private static long firstMondayOfFirstWeek(int year) {
  		final long janFirst = ymdToJulian(year, 1, 1);
  		final long janFirstDow = floorMod(janFirst + 1, 7); // sun=0, sat=6
  		return janFirst + (11 - janFirstDow) % 7 - 3;
  	}