In the new GUI, when I click to Download the configuration backup I got this dialog (firefox); and need to save with a name that is prone to error because I forgot the right file extension:
But in old GUI the right file name is used to save the file:
You are a machine!?
Seems related, the config backup file can be downloaded, just need to be renamed with the correct file extension, or hope for Linux to correctly open it with ark or the related application.