Flag 2 x 2 with Blue and Yellow Rectangle Pattern (Sticker)

[Magnus Forsberg]

-that sticker is numbered like the sticker sheet
-> in that case 56214 and its the first sticker of that sheet, so use index a -> 56214a.dat

No,
"Stickers from sheets with combo 5-digit/7-digit numbers should use the 7-digit number. "

https://www.ldraw.org/part-number-spec.html#sticker