He means that instead of the markers 1, 2, 3, 4 on the Leap Year indicator...
By: MTF : March 19th, 2016-23:54
Traditionally, the markers 1, 2, 3 and 4 indicate normal years 1 to 3 that have 28 days in February. Then in Year 4, there are 29 days. The suggestion to help people is to indicate for each year sector the actual number of days e.g. 28, 28, 28 and then 29...