How can I see which (system) apps are installed with which account? I have three different Google accounts on my phone, with one the default one. I want all apps to be installed on that account. I've just noticed that one app was installed with an account that is not under my control. Strangely enough this is a system app.
How can I see which apps are installed with which account?
System apps come with OS before even adding accounts. They have nothing to do with which account you use.
Google accounts matter only for user installed apps either if it is a paid app or if auto backup is enabled for that app and you backup your apps.
Only exception I can think of is that your device is rooted and you installed an app that can be made into a system app, and you are now assuming that this system app is associated with Google account.