A Google founder has more than doubled his financial contribution to the fight against a proposed wealth tax in California. New filings with the state show that former Alphabet president Sergey Brin donated $25m to a Super Pac dedicated to blocking the tax on top of $20m he had already given.Brin is not alone among Google’s top brass in upping his financial stake in the campaign against the ballot proposal. The company’s former CEO Eric Schmidt donated $1.02m, adding to a previous $2m contributi...