After " Build Standalone Package" I get temp/build folder that includes folders: bin, conf, legal, lib and xxx.exe file.
I didn't find Files folder with files at DirAssets.
I see. Now I get what you mean.
Based on my understanding, when you compile the project in Release, the files in assets folder are put inside the result.jar and can still be open with archiving tools like WinRAR.
result.jar/Files
When we choose "Build Standalone Package", the Files folder is compiled into the modules file (build/lib/modules).
I don't know any tools that can view it.
But if you continue to build the package using Inno Setup, then it is possible to reverse-engineering the exe file.