The documentation of Qt::SvgMiterJoin is not on a par with the other types of line join. It is only mentioned in the Qt namespace page (http://doc.qt.io/qt-5/qt.html#PenJoinStyle-enum).
What is lacking is:
- a picture on the Qt namespace page.
- mention and a picture on the QPen page (http://doc.qt.io/qt-5/qpen.html#join-style)
- (Bug!) explanation of the different interpretation of miter limit on the QPen page (QPen page)
- integration in the path stroking example.
Qt::SvgMiterJoin is more important than the Name suggests because this is the type of miter join and miter limit which is implemented not only in SVG but also in PDF. So any painting which has PDF files and PDF-based print engines as major targets should be based on Qt::SvgMiterJoin rather than Qt::MiterJoin!
(I don't know if any other paint engines have the same issue.)