Moral rights
An author's right to be credited and to object to the work being mangled – the part of copyright that can't be sold.
The concept comes from the French droit moral and was written into the Berne Convention in 1928. Most European laws, Sweden's included, grant a right of attribution and protection against derogatory alterations. Unlike the economic rights, they can't be transferred, only waived to a limited extent. The US barely recognises them, outside a narrow 1990 statute covering visual art.
For software they're mostly a legal footnote, but they explain why public domain dedications such as CC0 waive rights only "to the extent permitted by law". In much of Europe you simply can't give away your name on your own work, however keen you are to do so.