The capital S breaks the icon match.
It was broken in Plasma 5.6 => Plasma 5.7, so I guess I'll merge 5.12 => 5.14 => 5.15 => master, assuming we still need to backport to 5.14 for Debian?
https://github.com/KDE/plasma-workspace/blob/Plasma/5.12/dataengines/weather/ions/envcan/ion_envcan.cpp#L294
Do I bother putting FIXED-IN: 5.15.2 if there's no bug report?