Then consider it Creative Commons. That license is valid in Europe, I am sure, and it is the full equivalent of public domain.No, no, no. It's not about the authors' rights now. It's about Europe's law, in relation to PD. And in Europe, (1) it is illegal to "close", use PD for one's personal gains etc. Again, I would have to find that exact link/source(s). (2) Even if IPPOLIT authors rescind their rights, ownership etc to IPPOLIT codes, in Europe, it is still regarded as Public Domain. And there are laws in Europe regulating this. Which brings us back to (1). (3)Yes, Public Domain can be used by any persons how they like. Just NOT in Europe. If Robert Houdart lived outside of Europe, then it's a different ball game. See the difference now?
If it were illegal to give something away in Europe, I suppose that makes a good laugh anyway. Glad I don't live there.
If you want a free instance, then get Ippolit/Robbolito/Ivanhoe/Whatever and have at it. I fail to see how anyone could possible imagine harm in this scenario.