Was the expo init / advanced (experimental) is about?



I just noticed this choice when doing expo init on the last release:

out of curiosity I tried it out but it seems it need to be compiled first

[18:56:25] Error running app. Have you installed the app already using Xcode? 
Since you are detached you must build manually. 
Error: Process exited with non-zero code: 194```

Where can I find some documentation about this option? 
Will this "hybrid" system allows the Expo experience with some custom native modules or it is just a detached project from the start?