 // Ideally, we would be able to tie this to an iOS version rather than a compiler version, but such
 // a solution does not seem to be available for Swift.
 #if compiler(>=5.2)
-@available(iOS 13.4, *)
-extension MDCCatalogComponentsController: UIPointerInteractionDelegate {
   @available(iOS 13.4, *)
-  func pointerInteraction(_ interaction: UIPointerInteraction,
-                          styleFor region: UIPointerRegion) -> UIPointerStyle? {
-    guard let interactionView = interaction.view else {
-      return nil
-    }
-    let targetedPreview = UITargetedPreview(view: interactionView)
-    let pointerStyle = UIPointerStyle(effect: .highlight(targetedPreview))
-    return pointerStyle
-  }
-}
+  extension MDCCatalogComponentsController: UIPointerInteractionDelegate {
+    @available(iOS 13.4, *)
+    func pointerInteraction(
+      _ interaction: UIPointerInteraction,
+      styleFor region: UIPointerRegion
+    ) -> UIPointerStyle? {
+      guard let interactionView = interaction.view else {
+        return nil
+      }
+      let targetedPreview = UITargetedPreview(view: interactionView)
+      let pointerStyle = UIPointerStyle(effect: .highlight(targetedPreview))
+      return pointerStyle
+    }
+  }
 #endif
 
 // UIScrollViewDelegate

  }

  override func scrollViewWillEndDragging(
      _ scrollView: UIScrollView,
      withVelocity velocity: CGPoint,
      targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    let headerView = headerViewController.headerView
    if scrollView == headerView.trackingScrollView {
      headerView.trackingScrollWillEndDragging(

    //   "Use of undeclared type 'UIPointerInteractionDelegate'"
    // Ideally, we would be able to tie this to an iOS version rather than a compiler version, but
    // such a solution does not seem to be available for Swift.
    #if compiler(>=5.2)
      if #available(iOS 13.4, *) {
        let interaction = UIPointerInteraction(delegate: self)
        button.addInteraction(interaction)
      }
    #endif
    return button
  }()

  private let node: CBCNode
  private lazy var titleLabel: UILabel = {
