They mention a donation link: https://www.openbsd.org/donations.html

I wonder what their funding is like.

It is based upon what the OpenBSD Foundation gets. Last year:

https://www.openbsdfoundation.org/campaign2025.html

Now I am going to call out IBM. Last I checked, IBM uses OpenSSH on AIX, but gives a big fat 0. Microsoft has been consistent in donating a decent amount. And a surprise to me, Meta showed up donating last year, nice. I wish IBM would join the list too. Based upon:

https://www.openbsdfoundation.org/contributors.html