I had no idea that this had been put into Umbraco core! 😆 I'm happy that I can remove that extension method from my Contentment package in a future release. 😁

Yeah, I have used it in a project to remove Content Templates tree from settings section and added it to content section instead.

Removing the core tree:

public class TreeComposer : IComposer
{
    public void Compose(IUmbracoBuilder builder)
    {
        // Remove default Content Templates tree - this is added in content section in ContentTemplatesController.
        builder.Trees().RemoveTreeController<ContentBlueprintTreeController>();
     }
 }

and then registering a custom tree inheriting from ContentBlueprintTreeController:

[Authorize(Policy = AuthorizationPolicies.SectionAccessContent)]
[Tree(Constants.Applications.Content, Constants.Trees.ContentBlueprints, SortOrder = 10)] //TreeGroup = Constants.Trees.Groups.Settings
[PluginController(Constants.Web.Mvc.BackOfficeTreeArea)]
[CoreTree]
public class ContentTemplatesController : ContentBlueprintTreeController
{
    public ContentTemplatesController(
        ILocalizedTextService localizedTextService,
        UmbracoApiControllerTypeCollection umbracoApiControllerTypeCollection,
        IMenuItemCollectionFactory menuItemCollectionFactory,
        IContentService contentService,
        IContentTypeService contentTypeService,
        IEntityService entityService,
        IEventAggregator eventAggregator) 
        : base(localizedTextService, umbracoApiControllerTypeCollection, menuItemCollectionFactory, 
              contentService, contentTypeService, entityService, eventAggregator)
    {

    }

    protected override ActionResult<TreeNode> CreateRootNode(FormCollection queryStrings)
    {
        var root = base.CreateRootNode(queryStrings);

        if (!string.IsNullOrEmpty(root.Value.RoutePath))
        {
            // Update route to content section
            root.Value.RoutePath = root.Value.RoutePath.Replace(Constants.Applications.Settings, Constants.Applications.Content);
        }

        return root;
    }

    protected override ActionResult<MenuItemCollection> GetMenuForNode(string id, FormCollection queryStrings)
    {
        var collection = base.GetMenuForNode(id, queryStrings);

        if (collection.Value.Items.Count > 0)
        {
            foreach (var menuItem in collection.Value.Items)
            {
                if (menuItem.Action is ActionCreateBlueprintFromContent)
                {
                    var route = menuItem.AdditionalData["actionRoute"]?.ToString();

                    if (!string.IsNullOrEmpty(route))
                    {
                        // Update route to content section
                        menuItem.NavigateToRoute(route.Replace($"/{Constants.Applications.Settings}/", $"/{Constants.Applications.Content}/"));
                    }
                }
            }
        }

        return collection;
    }

}