src/vs/workbench/browser/parts/editor/tabsTitleControl.ts/TabsTitleControl/getTabAtIndex
class TabsTitleControl:	private getTabAtIndex(editorIndex: number): HTMLElement | undefined {
		if (editorIndex >= 0) {
			const tabsContainer = assertIsDefined(this.tabsContainer);

			return tabsContainer.children[editorIndex] as HTMLElement | undefined;
		}

		return undefined;
	}