How to get text value from cross-site iframe?

Hi, I want to get a text from an element that is behind 2 iframes. I was attempting to use executeScript to be able to get it with JavaScript but each time I was getting the iframe by its name, I didn’t catch anything. Then after some research I found that is because the iframes have different host from original URL, and that is a type of cross-domain (or cross-site) iframe. And it seems there is no way to get the elements inside iframes in cross-domain.

I’d like to know how can I do this? If I use F12 (developer tools) in chrome, I can see the value I want to extract. SourceExtract command would be for this task or another command?