But it's no longer a donation (regardless if that word is used or not) when you offer things like material support of the app in exchange for the money. Then it is actually a support contract. If they are not registered a non-profit in the US, they it's just regular income and they have to pay taxes on it. Because they made a profit.
My point is I don't believe this is a serious project worth giving money to until they can say they have resolved this with Apple.