In the day of releasing kubuntu 16.04  I use sudo do-relase-upgrade but nothing has been found then i`ve tried sudo do-release-upgrade -d  after the command that trigged an unwanted preparing for upgrade (to a xenial developer version) that messed up  my /etc/apt/sources.list and I want that muon updater to have a feature that reset the /etc/apt/sources.list back to it`s default state. and this feature to be trigged by a button that when the user clicks in to warn that his modifications to sources list will be deleted then if the user press OK to revert the /etc/apt/sources.list to it`s default version and if the user press return will close that dialog box and nothing will be happen.
and cancel the operation


Reproducible: Always