Comment by brettcannon

The specific restriction from my understanding is that a US non-profit that accepts money for a specific thing must spend every penny of that money only on that thing. So if the PSF was given $1,000,000 to solve a specific problem and while trying to do it they go bankrupt they still couldn't touch that money to stay afloat. So non-profits avoid that situation since they typically have enough to survive a year or so, but not enough to be able to restrict what they might need to do with their cash.