sources.list replaced by /etc/apt/sources.list.d/ubuntu.sources in deb822 format

[mahesh]

In last ISO sources.list has been replaced by /etc/apt/sources.list.d/ubuntu.sources in deb822 format
but software-properties-gtk seems unable to work with new format: https://bugs.launchpad.net/ubuntu/+s...s/+bug/2033949