Maybe more background to add to the story:

Originally, the source code of Waze clients was released under GPL, which AFAIR it was as branded as a part of the community-based map app.

But the company chose to not release the source code after v3.0. This is quoted from one of my emails.

    In reply to your inquiry "Hi, where can we get the latest waze code?":
    
    Thank you for your feedback.
    
    You can find source code for the old versions (up to 2.4) on our wiki - waze.com/wiki
    
    Version 3.0 and higher are no longer under GPL, and at the moment we are still considering if and how we will share the code for these versions.
    
    Best regards,

I guess Waze either 1) has obtained the agreements of all open-source contributors, or 2) has completely rewritten all related source code.