You can read the Adobe Data Layer in your browsers console by typing in "adobeDataLayer" and hitting enter (this is in the code execution area, not the filter).
However, reading it and using it to debug, you will have to know what events are triggering rules and what object paths are being accessed (as this is an event based data layer, and depending on the implementation, new data could be continually be added to the object, or the object could be cleared and replaced)