Updates: recently updated the pre-amble to include:
- a definition of "libre license" on the page
- reference to "libre share" - which is not copyleft
- (more like "one more step of freedom" - e.g. a derived work (or even unmodified copies) may be CC-BY if no other components disqualify CC-BY).
Wayne just reminded me of CC0. This would be equivalent to Libre Puro in that attribution is not required and all the freedoms apply. So, perhaps there is no need for the Libre Puro License, and it would be better as an emblem indicating that the resource is in a libre format or is (or is fully editable by) software libre, and not patent-encumbered, etc.