See: https://www.theguardian.com/us-news/2023/aug/26/silicon-valley-elites-buy-800m-land-new-city

Silicon Valley elites revealed as buyers of $800m of land to build utopian city

Group Flannery Associates, backed by prominent investors, quietly buy 55,000 acres of farmland in northern California

As best as I can find, here's a map of the purchased land:

And here's a screenshot of Solano County's zoning map:

Looks like the bulk of it is in various green agricultural zones.

If the developers want to build a city, presumably they will try to get their land re-zoned. Will this happen by 2030?

For now I'll plan to go by a "you know it when you see it" standard rather than any hard rules about % of land re-zoned. If it's substantially unclear, N/A. If you'd like to suggest improvements, these rules are fuzzy and subject to change until 1 October 2023.

See also