Extracting text from scorm packages

Hello, I've built a script that extracts the text from a course by loading up und.js or en.js files found in the locales folder (locales folder can be found in scormcontent folder).

What I've seen is, not all scorm packages have a "locales" folder inside "scormcontent" folder. 

I'm curious if this is a bug or if it has something to do with the Language Localization. 

What influences the absence of "locales" folder from "scormcontent" folder ? 

Thanks :)