@goo That is contradicting yourself - you say there is a license, but then all that's in there is the words "public domain" and it's not clear what that's meant to even mean or apply to.

If it was a COPYING file that said; "This software is released into the public domain worldwide, but if that is not possible in your jurisdiction, you have unlimited permission to copy, distribute and/or modify the software, even for commercial purposes. There is no warranty of any kind, express or implied.", that could possibly be valid, but that still misses a lot of issues that plague software.

You really need to use something as thorough as the CC0 or WPDD to validly place something in the public domain, or equivalent worldwide with certainty.