It’s perhaps understandable why the Society for the Reintroduction of the Bay Area Gizzly Bear stays under the radar …

(/joke)

Often when you see a vague reference like that it’s typically because the donor requested anonymity. It’s more common with individual donors though.

Sometimes anonymity is a condition of the gift.

They may have requested to be anonymous

People treat you differently if they think you have money or did something heroic. Sometimes people don't want to be treated any differently just because you have or did something special. If you liked who I was before you knew I had money, then I'll know you liked me for me, and not my money. The Bay Area foundation might be someone who made it rich in an IPO but doesn't want their friends to know about it.