pp-wp-snippet-list-shortcodes.php

// Add a custom function to create the meta box
add_action('add_meta_boxes', 'add_shortcodes_metabox');

// Function to add the meta box to the post edit screen
function add_shortcodes_metabox() {
    add_meta_box(
        'shortcodes-metabox', // Unique ID for the meta box
        'Available Shortcodes', // Title of the meta box
        'display_shortcodes', // Callback to display the meta box content
        'post', // Screen (post type) where the meta box will be displayed
        'side', // Context (side or normal)
        'low' // Priority (low for a less prominent position)
    );
}

// Function to display content of the meta box
function display_shortcodes() {
    global $shortcode_tags; // Correctly access the global shortcode_tags variable

    // Sort the shortcodes alphabetically
    $available_shortcodes = $shortcode_tags;
    ksort($available_shortcodes);

    // Output the list of all available shortcodes
    echo '<div class="categorydiv">';
    echo '<div class="tabs-panel">';
    echo '<ul id="categorychecklist" class="categorychecklist form-no-clear" style="">';
    
    foreach ($available_shortcodes as $shortcode => $callback) {
        echo '<li><pre><code>[' . esc_html($shortcode) . ']</code></pre></li>';
    }
    
    echo '</ul>';
    echo '</div>'; // End of "All" tab content panel
    echo '</div>'; // End of shortcodes container
}

function enqueue_custom_admin_styles() {
    echo '<style>
		#shortcodes-metabox .categorychecklist { margin: 0 }
		#shortcodes-metabox .tabs-panel { max-height: 212px }
        #shortcodes-metabox li pre code { margin: 0; display: flex }
    </style>';
}
add_action('admin_head', 'enqueue_custom_admin_styles');