Because they're a 501c3 organization, their tax filings are public. The most recent filing is tax year 2019, but there's a decent amount of detail.<p><a href="https://apps.irs.gov/app/eos/detailsPage?ein=824506840&name=Signal%20Technology%20Foundation&city=Mountain%20View&state=CA&countryAbbr=US&dba=&type=CHARITIES,%20DETERMINATIONLETTERS,%20COPYOFRETURNS&orgTags=CHARITIES&orgTags=DETERMINATIONLETTERS&orgTags=COPYOFRETURNS" rel="nofollow">https://apps.irs.gov/app/eos/detailsPage?ein=824506840&name=...</a>