src/vs/editor/browser/dnd.ts/addExternalEditorsDropData
export function addExternalEditorsDropData(dataTransfer: VSDataTransfer, dragEvent: DragEvent) {
	if (dragEvent.dataTransfer && !dataTransfer.has(Mimes.uriList)) {
		const editorData = extractEditorsDropData(dragEvent)
			.filter(input => input.resource)
			.map(input => input.resource!.toString());

		// Also add in the files
		for (const item of dragEvent.dataTransfer?.items) {
			const file = item.getAsFile();
			if (file) {
				editorData.push((file as FileAdditionalNativeProperties).path ? URI.file((file as FileAdditionalNativeProperties).path!).toString() : file.name);
			}
		}

		if (editorData.length) {
			dataTransfer.replace(Mimes.uriList, createStringDataTransferItem(UriList.create(editorData)));
		}
	}

	for (const internal of INTERNAL_DND_MIME_TYPES) {
		dataTransfer.delete(internal);
	}
}