The Blender project encourages originality and innovation in all aspects of the development process. We expect contributions or modification proposals on blender.org to be presented with original mockups and designs that are self-explanatory, using concepts and methods that build on top of the rich original design history of Blender itself.
Contributors to blender.org channels should avoid using references to proprietary or strictly copyrighted software products. In cases where it is essential to mention such a product, limit it to referring to public information that's allowed to be shared (press releases, promotion videos, wikipedia).
We do not allow copyrighted elements from proprietary software being added to any part of Blender, most importantly because that would violate the proprietary software’s EULA. Any user of proprietary software should be carefully aware that you don’t enjoy the freedom to share that. A freedom you obviously do have for everything we do within the Blender project.
The moderators and administrators on blender.org reserve the right to remove screenshots or texts they consider potentially damaging to Blender. In case you’re in doubt about posting something, please ask for advice from one of the Blender module team members.
— Blender Foundation, January 2021