That's exactly it. The $20 is not an assessed value of the code; it's to establish consideration. $1 would have been legal. It's legal to make asymmetric contra

That's exactly it. The $20 is not an assessed value of the code; it's to establish consideration. $1 would have been legal. It's legal to make asymmetric contracts that benefit one party more than the other, just not contracts that are completely one-sided. They probably did $20 just so it wouldn't seem quite as insulting. Anytime you see stories of "[insert name of rich CEO or politician] takes salary of only $1", that's why. They can't work literally for free, or the rest of the contract becomes nonbinding.