The link remains here until such time as the JED team remove it so that anyone interested can download it and take on development including update to J3 compatibility.
No support is available.
It doesn't display a "month from today's date" but rather displays the current month. Big difference.
If its the last day of the month, basically it just tells you the last 30 days and the current day, nothing for the future. Pretty hard to plan marine navigation ahead of time in this regard.