BBC say they have 'confirmed' it's Excel, though still a bit mysterious on how they've done that: https://www.bbc.co.uk/news/uk-54422505 https://www.bbc.co.uk/n

BBC say they have 'confirmed' it's Excel, though still a bit mysterious on how they've done that: https://www.bbc.co.uk/news/uk-54422505 https://www.bbc.co.uk/news/uk-54422505 Particularly, they reckon they were using the older XLS rather than XLSX format with the lower 65000 row limit - although that seems more like a deflection from the fact functionality limits weren't properly handled, tested or designed for.