Description of problem:
Welcome/Examples screen in qtcreator displays a combobox to select Qt version. But even if one selects the current version, the page is void of any example.
I have checked that some examples are installed
cd /usr/lib64/qt5/examples
[yves@Netbook-M4 examples]$ ls
assistant/  dbus/      examples.pro*  help/      network/  qml/  qtconcurrent/  quick/   script/  svg/    uitools/  xml/
corelib/    designer/  gui/           linguist/  opengl/   qpa/  qtestlib/      README*  sql/     touch/  widgets/  xmlpatterns/

According to documentation
https://wiki.qt.io/Qt_Examples_in_Qt_Creator
"Qt Creator looks up 'examples-manifest.xml' and 'demos-manifest.xml' files from subdirectories of the Qt doc directory (the one qmake -query QT_INSTALL_DOCS returns). "
qmake -query
...
QT_INSTALL_DOCS:/usr/share/doc/qt5
...
QT_INSTALL_EXAMPLES:/usr/lib64/qt5/examples
QT_INSTALL_DEMOS:/usr/lib64/qt5/examples
...
But there is no 'examples-manifest.xml' nor 'demos-manifest.xml' anywhere.
It seems that something is not build.