gistfile1.txt

<?php

/**
 * @class Export_Import_Install_Control
 */
final class Export_Import_Install_Control extends WP_Customize_Control {
    
    /**
     * @method render_content
     * @protected
     */
    protected function render_content()
    {
        $plugin = 'customizer-export-import';
        $nonce  = wp_create_nonce( 'install-plugin_' . $plugin );
        $url    = admin_url( 'update.php?action=install-plugin&plugin=' . $plugin . '&_wpnonce=' . $nonce );
        
        echo '<p>' . __( 'Please install and activate the "Customizer Export/Import" plugin to proceed.', 'text-domain' ) . '</p>';
        echo '<a class="install-now button" href="' . $url . '">' . __( 'Install &amp; Activate', 'text-domain' ) . '</a>';
    }
}