You need to set the correct app id - which has to be the same like the deskto file name. Which is mergers.
The app id currently is com.example.MeldRs:
$ WAYLAND_DEBUG=1 mergers
...
[4145598.980] -> xdg_toplevel#81.set_app_id("com.example.MeldRs")
...
If you change the app id to mergers I am very sure the correct app icon will be shown.
You need to set the correct app id - which has to be the same like the deskto file name. Which is
mergers.The app id currently is
com.example.MeldRs:If you change the app id to
mergersI am very sure the correct app icon will be shown.