#include <QMimeDatabase>
int main(int argc, char *argv[])
{
    qDebug() << QMimeDatabase().mimeTypeForFile("/path/to/test.tar.gz");
    return 0;
}
 

This code returns fundamentally different types between Qt 6.7.2 and Qt 6.8.

In 6.7.2 it returns "application/x-compressed-tar", in 6.8 it returns "application/gzip".

gzip is not correct, since gzip is a single compressed file, while x-compressed-tar is an archive of files, compressed with gzip.