Each Element is one cosmetic: type/name/group/cantBeBought/owner flags plus one Price per vesselRank 1-17 with duration -1 permanent, cost credits and goldCost gold. Lower goldCost to discount, set cantBeBought 1 to hide.
<Element type="0" name="battle_pass20_10" group="0" cantBeBought="1" ownerId="0" ownerReward="0.000000">
  <Price vesselRank="1" duration="-1" cost="0" goldCost="500" />
  <Price vesselRank="17" duration="-1" cost="0" goldCost="500" />
</Element>
Free-paint localhost: set every goldCost to 0. Keep all 17 rank lines per Element; deleting one rank makes that rank unable to buy it.
Additional Notes: 

Keep all 17 vesselRank lines per Element.

Comments

3 + 5 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.