macOS Finder does not use Freedesktop MIME icons. Options:
- Use Visual Studio Code with the bundled vscode-extension (heart icon in the editor); VS Code–compatible editors can load the same extension folder from their extensions path.
- To change a single file’s icon: Get Info → drag a .icns onto the small icon (manual).
- A proper default .ilu icon in Finder for all users requires an app bundle declaring a document type (UTI); not included in this minimal bundle.
