src/vs/workbench/browser/dnd.ts/extractFilesDropData
async function extractFilesDropData(accessor: ServicesAccessor, event: DragEvent): Promise<IFileTransferData[]> {

	// Try to extract via `FileSystemHandle`
	if (WebFileSystemAccess.supported(window)) {
		const items = event.dataTransfer?.items;
		if (items) {
			return extractFileTransferData(accessor, items);
		}
	}

	// Try to extract via `FileList`
	const files = event.dataTransfer?.files;
	if (!files) {
		return [];
	}

	return extractFileListData(accessor, files);
}