Minecraft wiki entry for Pre-flattening, associated text: potion with "Instant Health" effect has damage value 5 (= 5 + 0 + 0 + 0);
potion with extended "Slowness" effect has value 74 (= 10 + 0 + 64 + 0);
splash potion with tier II "Strength" effect has value 16425 (= 9 + 32 + 0 + 16384).