I was combing through the XML to see what bonuses cities could choose at the higher levels, and I ran across what looks like a typo.
<AbilityBonusOption InternalName="UnlockMinkOfRuvenna">
The internal name refers to small furry animals, instead of a grand institution of coins and precious metals. All of the other text appears to be spelled 'Mint', but the internal unlock is 'Mink'.