src/vs/base/browser/ui/list/listWidget.ts/List/onDidChangeActiveDescendant
class List:	private onDidChangeActiveDescendant(): void {
		const focus = this.focus.get();

		if (focus.length > 0) {
			let id: string | undefined;

			if (this.accessibilityProvider?.getActiveDescendantId) {
				id = this.accessibilityProvider.getActiveDescendantId(this.view.element(focus[0]));
			}

			this.view.domNode.setAttribute('aria-activedescendant', id || this.view.getElementDomId(focus[0]));
		} else {
			this.view.domNode.removeAttribute('aria-activedescendant');
		}
	}