.Desktop problems

[wavic]

The .desktop file is not like .exe. It's not a binary file. It's not an executable.
Anyway. Why not change it a bit? See 'Exec'.

[Desktop Entry]
Type=Application
Encoding=UTF-8
Name=SomeApp
Comment=SimiApp
Exec= /usr/bin/python3 /usr/share/applications/simi0op.py
Icon=/usr/share/icons/hicolor/48x48/apps/gw48.png
Terminal=true

OR

[Desktop Entry]
Type=Application
Encoding=UTF-8
Name=SomeApp
Comment=SimiApp
Exec=env python3 /usr/share/applications/simi0op.py
Icon=/usr/share/icons/hicolor/48x48/apps/gw48.png
Terminal=true

Search for an association of a mime type to an application.