I think it was chosen in spring, I would guess by @Combatglue, earnestly. The challenge is interesting, and the unlock is a no cost to production legacy item.
Most of the challenge topic is a list of fun challenges if they were made into contracts, but terrible ideas for being used as a list of proposition for roadmap unlocks.
Because the unlocks are chosen semi randomly to pad the idea.
Hence everyone bad reaction to the unlock, here and on reddit.