ASP.NET Core allows you to deploy your applications in a self-contained manner, ensuring they are platform-independent. This means that all the necessary runtime components are included with the application, eliminating the need for specific dependencies on the host system and providing portability.

In the URL /Books/Details/3, the "3" is a route parameter. Route parameters allow you to pass data from the URL to your controller actions, making it dynamic and allowing you to retrieve information specific to the value "3."

In EF Core, the class used to represent the database's context is typically named DbContext. This class acts as the entry point for interacting with the database, containing DbSet properties that represent tables and allowing you to define database operations. DbSet represents individual tables, while EntityContext and DataContext are not standard EF Core classes.

The primary distinction between Visual Studio and Visual Studio Code is that Visual Studio is a full-featured integrated development environment (IDE) with a wide range of features for various types of development, whereas Visual Studio Code is a lightweight, open-source code editor with extensibility for customizing and configuring it according to the developer's needs.

In the context of ASP.NET Core, "lightweight" refers to reduced memory usage and a small download size. ASP.NET Core is designed to use fewer system resources, making it efficient for hosting applications and reducing operational costs. This lightweight nature also allows faster startup times for applications.

Attribute routing in ASP.NET Core allows for centralized route configuration, making it easier to define routes for specific actions or controllers directly within the code using attributes. This provides a more intuitive way to specify routes and helps keep routing logic within the controllers where it belongs.

In a distributed deployment scenario, ASP.NET Core Identity uses a distributed lock mechanism to ensure that only one instance applies migrations at a time. This prevents conflicts and ensures database consistency. Allowing multiple instances to apply migrations concurrently could lead to issues such as data corruption or race conditions. While database transactions are used for consistency, they may not be sufficient for distributed deployments. ASP.NET Core Identity is designed to support distributed scenarios.

The primary role of "_Layout.cshtml" in ASP.NET Core is to define the webpage's structure and common elements, such as the header, footer, and navigation menu. It allows for consistent layout across multiple pages in your application.

The .NET CLI (Command-Line Interface) is a powerful tool for building, running, and managing .NET applications without relying on a full-fledged Integrated Development Environment (IDE). It allows developers to work efficiently in the command-line environment, making it a versatile choice for various .NET development tasks.

When using client-side validation in Razor forms, the unobtrusive Validation library is frequently used in conjunction with jQuery. This library allows you to define validation rules for form fields on the client side, providing immediate feedback to users without requiring a server round-trip. It's a crucial component for building responsive and user-friendly web applications.