See the stack of Flutter Navigator

Following steps:

1. Set a breakpoint where you want to inspect, which must be inside a builder function which has context, and run in Debug mode
   

2. Run your app to the break point

3. Open “Evaluate expression”
   

4. Evaluate Navigator.of(context)
   

5. Inspect the _history

In my example, you can see there are 2 routes in the history, with all relevant debuggable data.

Hope it helps