- Unknown|I don't know exactly
- Free licenses:
- PD|PD: public domain
- CC-by-sa-2.5|CC-BY-SA: Creative Commons Attribution ShareAlike 2.5
- CC-by-sa-4.0|CC-BY-SA: Creative Commons Attribution-ShareAlike 4.0
- GFDL|GFDL: GNU Free Documentation License
- GPL|GPL: GNU General Public License
- LGPL|LGPL: GNU Lesser General Public License