Some code to see what ASP.NET Core sees for routes and actions

Debugging ASP.NET Core Routing.cs

using Microsoft.AspNetCore.Mvc.ApplicationParts;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.Infrastructure;

public SomeController(
	IActionDescriptorCollectionProvider actionDescriptorCollectionProvider,
            ApplicationPartManager applicationPartManager)
{  }

[Route("routes")]
[HttpGet]
//source: https://github.com/ardalis/AspNetCoreRouteDebugger/blob/master/SampleProject/Controllers/RoutesController.cs
public IActionResult RoutesDeug()
{
	var routes = actionDescriptorCollectionProvider.ActionDescriptors.Items
		.Where(ad => ad is ControllerActionDescriptor)
		.Cast<ControllerActionDescriptor>()
		//.Where(cad => cad.ControllerTypeInfo.FullName.Contains("Plugin.Blah"))
		.Where(cad => (cad.ControllerName == "Category" && cad.ActionName == "Index")
		|| (cad.ControllerName == "CustomerBlah" && cad.ActionName == "Index")
		).ToList();

	var res = routes
		.Select(x => new
		{
			Action = x.RouteValues["Action"],
			Controller = x.RouteValues["Controller"],
			Name = x.AttributeRouteInfo?.Name,
			Template = x.AttributeRouteInfo?.Template,
			Contraint = x.ActionConstraints
		}).ToList();
	return Ok(res);
}

[Route("controllers")]
[HttpGet]
//source: https://docs.microsoft.com/en-us/aspnet/core/mvc/advanced/app-parts?view=aspnetcore-2.1#sample-display-available-features
public IActionResult ControllersDeug()
{
	var controllerFeature = new ControllerFeature();
	applicationPartManager.PopulateFeature(controllerFeature);

	var controllers = controllerFeature.Controllers
		.Where(ctrl => ctrl.FullName.Contains("Plugin.Blah"))
		.OrderBy(ctrl => ctrl.FullName)
		.ToList();

	return Ok(controllers);
}