build/lib/electron.ts/darwinBundleDocumentType
function darwinBundleDocumentType(extensions: string[], icon: string, nameOrSuffix?: string | DarwinDocumentSuffix, utis?: string[]): DarwinDocumentType {
	// If given a suffix, generate a name from it. If not given anything, default to 'document'
	if (isDocumentSuffix(nameOrSuffix) || !nameOrSuffix) {
		nameOrSuffix = icon.charAt(0).toUpperCase() + icon.slice(1) + ' ' + (nameOrSuffix ?? 'document');
	}

	return {
		name: nameOrSuffix,
		role: 'Editor',
		ostypes: ['TEXT', 'utxt', 'TUTX', '****'],
		extensions,
		iconFile: 'resources/darwin/' + icon + '.icns',
		utis
	};
}