Different file structure when using composer?

Hi,

I just noticed that the file structure of CI4 is different whether you install it using composer or do a 'manual' install ... what is the reasoning (if any reasoning at all) behind this? And should I worry about developing in either of these 'ways'? Yeah, I just see things potentially creeping up to bite me in the kneecaps …

I see no 'system' directory but a 'vendor' instead (containing the complete framework, including the 'system' folder) ...