Well the entire issue is that it's a tenant of the Tides Foundation which does file a 990 which is where all this info comes from about how the money is spent. It's not clear if tenant money is earmarked or otherwise set aside.
It is searchable. I cannot find a single mention of "Wikimedia" or "Wikipedia" or "Wiki" in it. So what does it tell us about what happened with people's Wikipedia donations?
https://en.wikipedia.org/wiki/Wikipedia:Wikipedia_Signpost/2...