NativeScript is backed by Progress.
1. NativeScript runtimes
2. Core modules
The core modules translate your calls into platform-specific calls that are executed at the runtime.
You can think of plugins as third-party libraries. These
4. Metadata, Type Conversion and Call Dispatcher
Finally, the Call Dispatcher takes care of making the actual calls to the native APIs and also receives the results and passes it back to the Type Conversion layer.
You need not know about the inner workings of the framework to start developing mobile apps using NativeScript, however, having a basic idea on how it works in theory is a good thing to learn.