This PHP class is designed for developers building custom themes who want to use the Bootstrap 4 front-end framework for their site navigation. It acts as a bridge, translating the standard menu structure from the platform's built-in menu manager into the specific HTML markup required by Bootstrap 4 components like navbars and dropdowns.

• Bootstrap 4 Navigation Output: The class generates the correct HTML classes and structure for Bootstrap 4 navigation bars, including support for dropdown menus, responsive toggles, and accessibility attributes.
• Uses Native Menu Manager: Developers can build and manage menus entirely through the standard admin interface. The walker handles the translation, so you don't need to hard-code menu HTML.
• Simple Integration: After including the class file, you activate it by passing a new walker instance to the wp_nav_menu() function in your theme template files.
• Fallback Functionality: Includes a fallback method to display a basic page list if no custom menu is assigned, ensuring navigation is always present.
• Customizable Depth: Allows control over how many menu hierarchy levels are rendered, which is useful for managing complex dropdown structures within the Bootstrap framework.