The key distinction being that loan will need to be repaid.
> The initial $50M in funding was a loan, not a donation, from Brian Acton to the new nonprofit Signal Technology Foundation. By the end of 2018, the loan had increased to $105,000,400, which is due to be repaid on February 28, 2068. The loan is unsecured and at 0% interest.[5]
The key distinction being that loan will need to be repaid.
> The initial $50M in funding was a loan, not a donation, from Brian Acton to the new nonprofit Signal Technology Foundation. By the end of 2018, the loan had increased to $105,000,400, which is due to be repaid on February 28, 2068. The loan is unsecured and at 0% interest.[5]
https://en.wikipedia.org/wiki/Signal_Foundation