The spreadsheet with the FY21 promotion board zones can’t be posted publicly, but you can find it here as long as you have your CAC card (make sure you pick your e-mail certificate):
It is posted under “Career Management.”
P.S. If you are Medical Corps, you actually don’t need the lineal list to find out when you are in zone. Because the Medical Corps is DOPMA exempt, you can just use the table on page 4 of the Promo Prep to figure out when you are in zone for promotion.