src/vs/workbench/contrib/notebook/browser/view/renderers/cellOutput.ts/CellOutputElement/_divSupportAppend
class CellOutputElement:	private _divSupportAppend(element: HTMLElement | null, mimeType: string) {
		if (element) {
			return element.getAttribute('output-mime-type') === mimeType;
		}

		return false;
	}