* Explicitly include some missing headers
* Use 'static const char*' for XPM icon
* Skip template parameters for qMakePair
* Constructor of QFileInfo is marked as 'explicit' now
* QString::fromLatin1() also accepts a QByteArray
* QDateTime::fromTime_t() is deprecated in Qt5 and has been removed in Qt6. Use QDateTime::fromSecsSinceEpoch()
* QDateTime::toTime_t() is deprecated in Qt5 and has been removed in Qt6. Use QDateTime::toSecsSinceEpoch()
* QApplication::globalStrut() is deprecated. Don't use it any more.
* QWidget::isTopLevel() is deprecated, use QWidget::isWindow()
* On lines where the variable type is obvious from inspection, avoid repeating the type using auto.
* When possible use a ranged for loop instead of begin() and end() iterators
Warning message was:
src/Gui/DownloadManager.cpp|295 col 54| warning: 'this' pointer cannot be null in well-defined C++ code; pointer may be assumed to always convert to true [-Wundefined-bool-conversion]
