file1.php

/**
* Gravity Forms Custom Activation Template
* https://gravitywiz.com/customizing-gravity-forms-user-registration-activation-page
*/
add_action('wp', 'custom_maybe_activate_user', 9);
function custom_maybe_activate_user() {
    $template_path = STYLESHEETPATH . '/gfur-activate-template/activate.php';
    $is_activate_page = isset( $_GET['page'] ) && $_GET['page'] == 'gf_activation';
    
    if( ! file_exists( $template_path ) || ! $is_activate_page  )
        return;
    
    require_once( $template_path );
    
    exit();