body: If I were to take license texts of publicy available licenses, such as the WTFPL, to add some paragraphs and create my own license, which I then ship with content created by me, would that be legal? What about AGB's for example?
  
  
  I'm sure companies put a lot of work/money in form of lawyers into writing the terms, and often it can't be prevented to make them open source.
  
  
  Three options seem to be plausible to me: (a) license not yet specified and anything possible (b) public domain (c) same license as the license if a license.
  
  
  (Initially intended to include the here used CC BY-SA 4.0, but after some additional search I found out that all CC licenses are itself licensed public domain. The question remains for the WTFPL for example, which is clearly copyrighted but without a license for the license given. Could use of the text be revoked / sued?)
  
  
  
title: What's the license of a license?