Change max chars in Onebox - enlarge your Onebox?

I was now able to set up a dev box via this topic: How to edit the discourse files? A development box? - #11 by mikechristopher

Can anybody tell me where to find the file responseble for the amazon data ripper.

It seems like is is not the file I thougt it was:

https://github.com/discourse/onebox/blob/master/lib/onebox/engine/amazon_onebox.rb

As there are no such file in my system. Even then the data output is like this on my dev box, with stars info and ISBN etc

https://www.amazon.com/Pathology-Physical-Therapist-Assistant-2e/dp/032339549X

Thank you.