cannot launch from gnome-software
When you install from gnome-software, it downloads and installs but the launch button does not work. After you hit launch, nothing appears to happen. Then, after a while, the following notification appears:
"is bitmaskd running? Start bitmask and try again."
The application is installed and will work if you launch it in a different way (e.g. run riseup-vpn.launcher from the command line or run via the meta key app launcher)