[mycl]

If I understand correctly, the issue is moral rights (https://en.wikipedia.org/wiki/Moral_rights). In some jurisdictions, including Germany, these rights cannot be waived.

For example, in such a jurisdiction, if I release a piece of code under a public domain equivalent license, you would have to give me credit as the author even if the license explicitly says you don't have to: the right to be identified as the author is a moral right that I cannot waive, legally.