Qmake clarification (greaterThan & app_bundle)?

[CroCo]

I want kindly to know what do the following lines mean in .pro file and when should I use them?

@greaterThan(QT_MAJOR_VERSION, 4): QT += widgets@
and
@CONFIG -= app_bundle@

I'm using mac and Qt 5.

[dbzhang800]

For Qt5,

@
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
@

equals

@
QT += widgets
@

which is needed when you using QtWidgets module.

@
CONFIG -= app_bundle
@

is needed when you don't want to create a app bundle. For example, when you create a console application.

[CroCo]

@Robot, thank you so much for being helpful.