Xenon is built using the MEAN stack. The sentiment logic can be found on the front-end, at src/app/news/news.component.ts
Visit the Xenon App
[2020 SEPT] Xenon is rewritten (ujjwal-kr/positive-vibes) in the MERN stack with features like authentication and variable sentiment analysis, it can be found here
The news App's API is rewritten and hosted withing the positive vibes app here