I don't think that there is SE site for your question.

[Web Applications](https://weapps.stackexchange.com) could be the closest site, as the question is about a Google web app, but the scope of this site is about using a web application, not about the data sources per se. Maybe you could make a related question like where to check the data source of an specific query / result. 

[Earth Science](https://earthscience.stackexchange.com/) has a some way related questions:

- https://earthscience.stackexchange.com/q/2959/14596
- https://earthscience.stackexchange.com/q/2813/14596