Ok, testing in Ubuntu MATE 18.04. Updated to version 0.5.2ubuntu14.2 from bionic-proposed.
$ UPDATE_MANAGER_FORCE_BACKEND_SYNAPTIC=1 apturl apt://gnome-calculator
All good, the package is installed successfully.
Ok, testing in Ubuntu MATE 18.04. Updated to version 0.5.2ubuntu14.2 from bionic-proposed.
$ UPDATE_ MANAGER_ FORCE_BACKEND_ SYNAPTIC= 1 apturl apt://gnome- calculator
All good, the package is installed successfully.