Overrides the default 'Featured Image' label

<?php
/**
 * Register the Book custom post type.
 */
function km_register_book_post_type() {
	register_post_type( 'company', [
		'public'   => true,
		'supports' => [ 'title', 'editor', 'thumbnail' ],
		'labels'   => km_get_book_cpt_labels(),
	] );
}
add_action( 'init', 'km_register+book_post_type' );
/**
 * Get the labels for the Book custom post type.
 */
function km_get_book_cpt_labels() {
	return [
		'name'                  => _x( 'Books', 'Post type general name', 'textdomain' ),
		'singular_name'         => _x( 'Book', 'Post type singular name', 'textdomain' ),
		'menu_name'             => _x( 'Books', 'Admin Menu text', 'textdomain' ),
		'name_admin_bar'        => _x( 'Book', 'Add New on Toolbar', 'textdomain' ),
		'add_new'               => __( 'Add New', 'textdomain' ),
		'add_new_item'          => __( 'Add New Book', 'textdomain' ),
		'new_item'              => __( 'New Book', 'textdomain' ),
		'edit_item'             => __( 'Edit Book', 'textdomain' ),
		'view_item'             => __( 'View Book', 'textdomain' ),
		'all_items'             => __( 'All Books', 'textdomain' ),
		'search_items'          => __( 'Search Books', 'textdomain' ),
		'parent_item_colon'     => __( 'Parent Books:', 'textdomain' ),
		'not_found'             => __( 'No books found.', 'textdomain' ),
		'not_found_in_trash'    => __( 'No books found in Trash.', 'textdomain' ),
		// Overrides the “Featured Image” label
		'featured_image'        => __( 'Book Cover Image', 'textdomain' ),
		// Overrides the “Set featured image” label
		'set_featured_image'    => __( 'Set cover image', 'textdomain' ),
		// Overrides the “Remove featured image” label
		'remove_featured_image' => _x( 'Remove cover image', 'textdomain' ),
		// Overrides the “Use as featured image” label
		'use_featured_image'    => _x( 'Use as cover image', 'textdomain' ),
    ];
}