Creating new account.

Couldn't found any archived post, which could answer my question.
I'm curious if there is any chance, firstly to find and then modify a script which is responsible for user's account creation? I would like to put some extra files to public_html directory straight after new user is set up. Is that possible, without digging in the core cwp files?

I am also wondering what script CWP uses for adding new users. I assume it is currently mostly in PHP, but it should still be possible to trigger it from CLI. I am trying to add users with specific subdomains which will later be used to configure non-web services but want to keep it consistent with CWP account system.