The content of file xl/calcChain.xml is malformed.

[nicoxb]

This lib generated xl/calcChain.xml is a styleSheet file;

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<styleSheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">

But the document standard should be calcChain file;

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<calcChain xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">

Here, use style as calcChain content: https://github.com/QtExcel/QXlsx/blame/700bda6a83f675ed1d2d8d359b23f18619dd64c7/QXlsx/source/xlsxdocument.cpp#L424-L426

This issue occurs when other libraries parse xlsx files generated by this library.