This file was destroyed, emptied by Affinity Designer v2.0.3! (see earlier post). Thank you for that. Stunning and jawdropping.
Version 2 claims the file type is "not supported" - then your customers think that there is actually some content in the file that Affinity cannot read. So better to tell them that the file contains significantly less content than expected...
You might add "It's not unlikely that Serif Software lost all your content and work, perhaps distracted by 'setting new standards', yet we remembered the filename! You could say we saved a percentage of your work. Zero is also a percent."
Lost file thread: