Blender itself is released under the GNU General Public License.
Except where otherwise noted, the content of the Blender Developer Documentation is available under a Creative Commons Attribution-ShareAlike 4.0 International License, or any later version. Excluded from the CC-BY-SA are logos, trademarks, icons, source code and Python scripts.
Please attribute the “Blender Developer Documentation Team” and include a hyperlink (online) or URL (in print). See recommended practices for attribution for details.
This means that after contributing to the documentation you do not hold exclusive rights to your text. You are, of course, acknowledged and appreciated for your contribution. However, others can change and improve your text in order to keep the documentation consistent and up to date.
If you have questions about the license, feel free to contact the Blender Foundation: foundation (at) blender (dot) org
The history of contributions and changes can be found at these locations.