Add ‘page template’ column to dashboard for CPTs

<?php
// add new column to the columns array
function wpse267793_columns($columns) {
    // Column name
    $columns['template'] = 'Template file';
    return $columns;
}

function wpse267793_show_template_columns($name, $post_id) {
    // get template file name from post meta
    $template = get_post_meta($post_id, '_wp_page_template', true);
    echo $template;
}

// change 'CPT' to the relevant custom post type
add_filter('manage_CPT_posts_columns', 'wpse267793_columns');

add_action('manage_CPT_posts_custom_column',  'wpse267793_show_template_columns', 10, 2);

• manage_posts_custom_column
• manage_posts_columns