Installer Password

The password requested is the login password for the User name shown (not to be confused with an Apple-ID password).

It is not specifically an Installer password, but is required to modify certain system directories to complete the installation..

There is no Installer password.

If you are getting a request for password, it is likely to be for the Admin account shown in the dialog box. If your name is the account shown, then your login password is what is required.

If it is asking for BOTH an Account AND password, that would be any Admin User account name and the password that matches it. For most Users, the FIRST (or only) account created is the Admin.