Decompile flutter release apk. Where to find source code?

Question

I have built a flutter apk in release mode and I would like to test if my app is really obfuscated and my code cannot be read. So I tried to decompile the apk using the APK Decompiler.

I had many files after decompiling. The question now is: What is the file that contains the source code and how do I know if it can be read or not?

I have some doubt on libapp.so, is it?

Solution

I confirmed my doubt when I was to able to open the libapp.so (shared object) file using Ghex and I have found some words of my code (like text and some style proprieties) but the source code is really obfuscated and it cannot be simply read.