What is vendor "support"?

I am happy to get a timely answer as a kind of acknowledgement, even if a solution might take much longer.

For bugs in the software I will either buy an upgrade if available or expect a fix/explanation for the most recent version if I am using it. I do not expect support for legacy versions.

I am happy to donate if the error is on my site but the developer took time to look into it to find out about it.