I have been developing a mobile game with Godot 2, and so far it has been working well. I have used a test phone with 16:9 display and everything has worked fine.
However, yesterday I bought a new phone with 18:9 display (LG Q6). It offers scaling option, so it automatically runs the app in some kind of compatibility mode (16.7:9), and the aspect ratio for each app can be manually changed to 18:9. After some research I noticed that even though most games I downloaded and tried are run in the compatibility mode (probably they don't just have support for 18:9 yet), some of them run immediately in 18:9 and there is no need to change it by hand.
How does Godot deal with aspect ratios bigger than 16:9? I have been struggling to get my game to automatically cover the whole screen and tried many different solutions but none of them satisfies me.