post_type_for_plugin.php

<?php
register_post_type( 'myplugin',
    array(
        'labels' => array(
            'name' => 'My Plugin',
            'all_items' => 'View All Rules',
            'add_new' => 'Add Rule',
            'add_new_item' => 'Add New Rule',
            'edit' => 'Edit Rule',
            'edit_item' => 'Edit Rule',
    	),	        	
        'public' => false,
        'show_ui' => true,
        'menu_icon' => 'dashicons-format-image',
        'supports' => array('title')
    )
);

// https://developer.wordpress.org/resource/dashicons/