Man pages matching name qwtscaleengine in section 3:

QwtScaleEngine.3.en	debian 10 / libqwt-doc
QwtScaleEngine.3.en	debian 10 / libqwt5-doc
QwtScaleEngine.3.en	debian 11 / libqwt-doc
QwtScaleEngine.3.en	debian 12 / libqwt-doc