Public domain is a thing in the EU but not releasing anything into public domain.
In Germany, I cannot renounce my copyright to anything. I can give you an indefinite, unrestricted license to do whatever but I still own the copyright. It will only ever become public domain 70 years after my death, not a day sooner or later.



















Not quite, this does have certain legal implications. Check out the CC0 license’s “Public License Fallback” text: https://creativecommons.org/publicdomain/zero/1.0/legalcode.en#fallback
The “license to do whatever” is more like a “license to do whatever except for whatever a court ruled I cannot give a license for”.