Provide a desktop entry file

[SyntaxOverflow]

Just a thought and I'm open to discussion.
How about distributing a desktop entry file?
For example the following works (an official icon is still missing):

/usr/share/applications/umu.desktop

[Desktop Entry]
Type=Application
Name=umu-Launcher
Comment=Run applications with Proton outside of Steam
Exec=umu-run %f
Categories=Game;Utility;
MimeType=application/x-ms-dos-executable;
PrefersNonDefaultGPU=true

[cD1rtX3]

application/x-ms-dos-executable is, as the name suggests, an MS-DOS executable and nothing else. Windows NT executables have mimetype application/vnd.microsoft.portable-executable.