Waterfox uses a generic icon in the task manager instead of its own
Screenshot attached. Waterfox is the farthest left and right icons. Installed from Flathub.
Solution
- Open Waterfox
- Right-click the title bar and select More Actions > Configure Special Window Settings…
- In the Window Rules window, select Add Property… > Desktop file name
- In the box next to Apply initially, enter
net.waterfox.waterfox - Click Apply