The city and the people who live in it? Municipal bonds? Firezone income & sales taxes? It's like a special assessment in a condo when you haven't been managing your reserves properly and by law / ADA you MUST fix your elevator to make your building accessible for people who cannot walk up stairs.

As to how? Like many other govt infrastructure projects, eminent domain. Except this land nobody will be living on, it will probably just be uninhabited farm or forest land or already owned by the state.

If we're talking about New Almaden, it isn't even a city. Just an unincorporated small community in Santa Clara county. There is no realistic way to fund major fire safety projects there. The county is tapped out, there is no way to raise taxes significantly, and other more heavily populated areas have higher priority.

We made roads & electric services to that place, I think a small gravel firebreak for their small community is not so much of a stretch.

Sure there's a way to finance it! Make everyone else in the country subsidize New Almaden! Works for hurricane and tornado areas too!