src/vs/workbench/contrib/notebook/browser/view/renderers/backLayerWebView.ts/BackLayerWebView/getRendererData
class BackLayerWebView:	private getRendererData(): RendererMetadata[] {
		return this.notebookService.getRenderers().map((renderer): RendererMetadata => {
			const entrypoint = this.asWebviewUri(renderer.entrypoint, renderer.extensionLocation).toString();
			return {
				id: renderer.id,
				entrypoint,
				mimeTypes: renderer.mimeTypes,
				extends: renderer.extends,
				messaging: renderer.messaging !== RendererMessagingSpec.Never,
			};
		});
	}