QwtPlotSpectroCurve(3) on Linux
The text c3e3dc015548, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster) shipped it. The page shows this text now.
Curve that displays 3D points as dots, where the z coordinate is mapped to a color.