i have found this license file:
fritzing-0.9.2b.linux.AMD64/parts/svg/core/LICENSE.txt:
All graphics and documentation of Fritzing are licensed under
Creative Commons Attribution-ShareALike 3.0 Unported.
See CC BY-SA 3.0 Deed | Attribution-ShareAlike 3.0 Unported | Creative Commons for the full description.
This means that you may publish circuits and diagrams that you create with
Fritzing and that use these graphics – as long as you credit us, and
publish your works under the same license.
A credit can be as simple as “this image was created with Fritzing.”
so if iam interpreting this right i am not allowed to embed a image of for example the breadboard view in an closed source document?!
thanks for clarifying this 
You can embed fritzing image(s) in a closed source project. We just ask for you run the Fritzing name if you use any pictures from inside the breadboard view. A simple, made using Fritzing giving credit to Fritzing somewhere in your project ie; credits section. or an embedded/embossed fritzing logo on the picture(s) used, that would also work. If you export this said image from inside fritzing, this credit is already embedded in the lower right-hand corner.
See Fritzing’s FAQ
http://fritzing.org/faq/
Half way down. What about the circuits that I created with Fritzing?
Hope this helps answer your question.
1 Like
thanks @landracer !
yes it answers my question!
the attribution in this way is easy and doable 
fritzing is a nice tool to work with for documentation things!
@s_light
You’re welcome! Hope your project is going as smooth as possible! 
Thanks for using Fritzing!! Good Luck!!
Can I use the PCB made by Fritzing to grant my own licence, such as robot controller board, and produce it for selling?