Fra Wizards of The Coast:
The Brothers’ War Prerelease Pack contains 6 The Brothers’ War Draft Boosters, 1 foil-stamped rare or mythic rare card, 1 MTG Arena code card (only available in select regions), 1 deck box, and 1 Spindown life counter.
Each The Brothers’ War Draft Booster contains 15 cards and 1 token/ad card, including 1 card of rarity Rare or higher, 1 card of rarity Uncommon or higher, 3 Uncommon cards, and 10 Common cards. Traditional Foil Borderless Mythic Planeswalker in <1% of boosters. Land card replaces a Common in 25% of boosters. Traditional Foil of any rarity replaces a Common in 33% of boosters.