WP - Assign to page separated template file and extend pages status texts

extend-bages-status-backend.php

<?php

add_action( 'admin_head-edit.php', 'edit_post_change_title_in_list' );


function edit_post_change_title_in_list() {
    add_filter( 'display_post_states', 'use_template_as_post_state', 100, 2);
}
function use_template_as_post_state( $post_states, $post ) {
    $available_templates = get_page_templates($post);
    $post_template_file = get_post_meta( $post->ID, '_wp_page_template', true );
    ksort( $available_templates );
	// for displaying in status page tempate name
    foreach ( array_keys( $available_templates ) as $template ) {
        if($available_templates[ $template ] == $post_template_file) $post_states[] = __('Template: ', 'textdomain').$template;
    }

    // Extendfor display page archive for page-template.php 
    if ( $post->post_type === 'page' ) {
        global $option;
        if ( $option['archives-projects'] == $post->ID ) {
            $post_states[] = '<small>'.__('Archive for projects','textdomain').'</small>';
        }
    }

    return $post_states;
}

page-template.php

add_filter( 'template_include', 'archive_for_peojects', 99 );

function archive_for_peojects( $template ) {

	global $post, $option;

	if ( $post->ID  == $option['archives-projects'] ) {
		$new_template = locate_template( array( 'template/archive-projects.php' ) );
		if ( '' != $new_template ) {
			return $new_template ;
		}
	}

	return $template;
}

Simple way to assign to page that you want (id is from $option['archives-projects'] or whenever you save this page ) a separated file used as template for this page.
Nice way to build special archives based on custom files, and add to option a way to assign page.

And second file is for add more info in backed for page status title.