Where does Kindle app on Sony store notes?

[Talayero]

Hi,
I'm using Kindle app on rooted Prs-T1.
When I'm reading a book that I've bought in Amazon there's no problem to export notes and underlines, because I can see them in my Amazon Kindle page when I synchronize the book.

But the thing is I read a lot of e-books that are not from Amazon.

How could I export that notes from my Sony Prs-T1?

They say in Kindle device you can find a My clippings.txt file with all the notes and underlines, but in the Sony there's not such a file.

However there must be some file to contain the notes, because you can see them when you chose to see them in the Kindle app installed in Sony device.

I couldn't find an answer after hours searching internet.
Has anyone some idea about it?

Thank you in advance.