LaSSI (the Last Starship Save Inspector) is a free, open source, cross-platform, fan-made tool for inspecting and editing save files for "The Last Starship" by Introversion Software (https://www.introversion.co.uk/introversion/). Cross-platform UI made possible by Eto (https://github.com/picoe/Eto)
It's currently possible (on Mac) at least to close the main window by accident (losing any changes) and put LaSSI in a unrecoverable state.