I manually checked the 15.4 DVD, LiveCD and 15.5 DVD and realized that if user choose the GNOME system role, distribution-logos-openSUSE-icons is really put into the final system. However, if you select Generic Desktop and then mark GNOME Desktop Environment (Basic), systemd-icon-branding-openSUSE is set. This is also inherent in LiveCD, systemd-icon-branding-openSUSE is installed there (but after installation there is distribution-logos-openSUSE-icons). It was necessary to first check a simple installation through system roles, and not to conclude that how the error was spreading based on how I personally install the system. I apologize. In any case, the changes in the comment#5 will allow both installations with distribution-logos-openSUSE-icons and with systemd-icon-branding-openSUSE to display the icon.