Many Snaps, such as Firefox, do not appear to support custom accent colors on KDE

I’m noticing some strangeness regarding accent colors with Snaps on KDE.

The most obvious when running a fresh Kubuntu 22.04 install is that Firefox does not adjust its accent color when choosing a custom one (like this pleasant, eye-searing green) in KDE’s system settings. This also applies to GTK3-based Snaps, and even some KDE Snaps like Neochat or Okular.

This would be easy to write off as “oh, it’s because of the sandbox/confinement!”, but for whatever reason, the KCalc Snap is green (and unlike the Kate Snap, it’s using strict confinement, not classic)! This leads me to believe that it should be possible to get accent colors working on at least the other KDE Snaps!

Hopefully there is also a way to get accent colors working on GTK3 based Snaps like Firefox. It is a minor detail, but it would really help to make the Kubuntu experience feel nice and well-integrated!

Bumping this since it seems to have gone under the radar.