A recent example of this is the python-is-python2 transition and systems trying to upgrade to Ubuntu 20.04 but not having universe enabled (where python-is-python2 is located) and that preventing the upgrade from being calculable.
A recent example of this is the python-is-python2 transition and systems trying to upgrade to Ubuntu 20.04 but not having universe enabled (where python-is-python2 is located) and that preventing the upgrade from being calculable.