Custom post state

add_filter( 'display_post_states', 'mx_custom_post_state', 10, 2 );

function mx_custom_post_state( $post_states, $post ) {

    if( $post->post_name == '404-error-page' ) { // upiši slug stranice
        $post_states[] = 'Fulao si sve';  // upiši željeni "opis"
    }

    return $post_states;
}