QStringView/QLatin1String::arg documentation

Where can be found the documentation of QLatin1String::arg and QStringView::arg mentionned here https://code.qt.io/cgit/qt/qtbase.git/tree/dist/changes-5.14.0/?h=v5.14.0#n210 ? neither on https://doc.qt.io/qt-5/qstringview.html nor on https://doc.qt.io/qt-5/qlatin1string.html. Yet, documentation seems to be written in https://code.qt.io/cgit/qt/qtbase.git/tree/src/corelib/text/qstringview.cpp#n531

Additionnaly, how should one choose between QLatin1String("....").arg() / QStringLiteral("....").arg() / QStringView("....").arg(), appart from obvious (but very rare) cases where the formatting string cannot be known at compile time ?