Description
Reddit link: Flag of the Archdukedom of Gutnisia (Gotland, 1808-present; ATL) (lore in comments)
This is the flag of Gotland in an alternate timeline during the Finnish War of 1808-09 when the people of Gotland decided to revolt against both the Russian troops for the occupation of their land and the Swedish monarchy for ignoring them too long. The proportions are 28:37 (based on the flag of Denmark), but the dimensions are unique. Instead of 12-4-12:12-4-21 of the Danish flag, the ATL Gutnish flag uses 10-2-4-2-10:10-2-4-2-19. It is a yellow-fimbriated green Nordic cross on a dark blue field.