This is a legacy project for gsm signal collection in a modern android 8 phone. It is being discontinued because the goal was to perform indoor location with gsm signals but modern phones usually throttle the signal to the 6-8 strongest gsm cells and due to privacy concerns its cell id and detailed information are no longer provided by modern mobile SDK platforms such as Android.
If you are looking for an indoor location and mapping solution you can take a look at my repositories.