Comment # 59 on bug 1199020 from Stefan Hundhammer

My steadily growing collection of notes about this DPI and font size issue:

  https://gist.github.com/shundhammer/79d534b8452554b16fb2f667f58290f9

One noteworthy intermediate result is that Qt introduced a "rounding policy"
for its scale factor with Qt 5.14 (i.e. not so long ago; right now we have 5.15
in TW), and it defaults to "Round", i.e. it will be rounded to the next integer
number; so in practice, it's either 1.0 or 2.0, not 1.5 or similar which it
might have used in the past; thus maybe the drastic increase of font sizes from
a certain DPI value on.