Understandable Public License v0.9 - "A legal document minus the legalese."
source work: Work used by derivative authors that is licensed with this license.
source authors: People who worked on the source work.
derivative work: Work that uses any portion of the source work.
derivative authors: People who worked on the derivative work.

Freedom #0: This license may be wrapped by any license that does not infringe on
Protections #0, #1, #2, #3 or Freedom #0 (only Freedom #1 may be infringed).

Freedom #1: Redistribution or sale with or without modification is permitted.

Protection #0: A copy of the source license must be distributed along with
all forms of any public or private redistribution of source or derivative
work. The source license may not be edited by derivative authors.

Protection #1: The source authors must be credited anywhere that the derivative
authors are credited for the derivative work. Ex.'s code, websites,
documentation, the about, easter eggs, ads, etc.

Protection #2: The source authors are not liable for anything.

Protection #3: Source work must contain an easily locatable notice, link to,
or copy of the license that cannot be removed by derivative authors.