SUMMARY

In a plasma wayland session, if chromium is configured with wayland settings (--enable-features=WaylandWindowDecorations --ozone-platform-hint=auto) then the icon shown in the titlebar and task manager  is the yellow "W" circle, the default wayland icon, regardless of the icon in specified in a custom desktop file.

I have multiple chromium profiles and I create a desktop file for each in ~/.local/share/applications/. Each desktop file gets their own icon, and specifies --user-data-dir in the cmdline. 

The icon works as expected in these other scenarios:  
- In a plasma x11 session, the icons work as expected. 
- In a plasma wayland session, the icons work as expected if chromium is running with xwayland. 



STEPS TO REPRODUCE

1. Create a desktop file for "Chromium-Extra". 
- create a folder for the profile in ~/chromium_profiles/extra
- create an icon for the profile in ~/chromium_profiles/_icons/Chromium_Logo-green.svg
- create the desktop file  ~/.local/share/applications/chromium-extra.desktop with the following contents:
```
[Desktop Entry]
Version=1.0
Name=Chromium-Extra
GenericName=Web Browser
Exec=/usr/bin/chromium --class=Chromium-Extra --user-data-dir=/home/xxxx/chromium_profiles/extra %U
StartupNotify=true
Terminal=false
#Icon=chromium
Icon=/home/xxxx/chromium_profiles/_icons/Chromium_Logo-green.svg
Type=Application
Categories=Network;WebBrowser;
MimeType=application/pdf;application/rdf+xml;application/rss+xml;application/xhtml+xml;application/xhtml_xml;application/xml;image/gif;image/jpeg;image/png;image/webp;text/html;text/xml;x-scheme-handler/http;x-scheme-handler/https;
Actions=new-window;new-private-window;

[Desktop Action new-window]
Name=New Window
Exec=/usr/bin/chromium --class=Chromium-Extra --user-data-dir=/home/xxxx/chromium_profiles/extra

[Desktop Action new-private-window]
Name=New Incognito Window
```

2. Set ~/.config/chromium-flags.conf to
```
--enable-features=WaylandWindowDecorations
--ozone-platform-hint=auto
```

3. From the application menu, launch Chromium-Extra

OBSERVED RESULT

- the application menu shows Chromium-Extra with a custom icon
- when it is launched, there is a brief ~1 second window where the taskbar shows an item titled "Chromium-Extra" with the custom icon, alongside additional windows (from the previous session) which have the yellow W icon.
- the "Chromium-Extra" in the tasbkar with the correct icon disappears after ~1 second, and the other windows remain with the yellow W icon
- the windows are correctly grouped together in the taskbar, separate from other chromium instances

EXPECTED RESULT
- all windows launched from Chromium-Extra have the custom icon, not the yellow W icon

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.111.0
Qt Version:  5.15.11

ADDITIONAL INFORMATION

If I use the debug console (qdbus org.kde.KWin /KWin org.kde.KWin.showDebugConsole), and inspect one of the windows, it shows the desktopFileName as "chromium (/home/xxx/chromium_profiles/extra)". I'm unsure why it isn't "Chromium-Extra". The icon field is blank, but it seems blank for every other application that has an icon too.