The unlicense is considered problematic in various jurisdictions, among them Germany - under German law, you cannot relinquish certain rights that are associated with the author at all. Dedicating something to the public domain is not a valid concept here. This means the whole license could be declared invalid in court. Other jurisdictions may be similarly problematic- thus the fallback to MIT

There’s a stackoverflow post that discusses some of the issues https://softwareengineering.stackexchange.com/questions/1471...