I think it means whatever you want. I read it as if you are able to make money using Caddy wouldn't it be fair to share it with the developer. I think there is

I think it means whatever you want. I read it as if you are able to make money using Caddy wouldn't it be fair to share it with the developer. I think there is a sub-text that implies if you sponsored Caddy and needed some extension or support that is available also. Before Open Source was codified the was an attitude where the software is free but the documentation costs money.