Comment # 12 on bug 1202837 from Atri Bhattacharya

(In reply to C J from comment #9)
> By default qt6 scaling was fine, but qt5 was too big (when using 150% font
> scaling in Gnome).
> 

This is because, according to
<https://doc.qt.io/qt-6/highdpi.html#environment-variable-reference>
the default scale factor rounding policy for Qt5 is `Round`, while for Qt6 is
`PassThrough`. Setting the env variable
`QT_SCALE_FACTOR_ROUNDING_POLICY=PassThrough` ensures you get the same correct
scaling across Qt5 apps just as you would by default with Qt6 apps.

I do not have Qt6 apps to try this myself, so if you could give this a shot,
that would be useful and much appreciated. If you do, please remember to first
unset the other QT DPI related env variables you may have set from earlier.