editing footer text in JBST theme

The footer credits are output by the jbst_credits custom action, which has the jbst_custom_credits() callback:

function jbst_custom_credits() {
    if(get_theme_mod('footer_credits') <> "") {echo    get_theme_mod('footer_credits');}
    else {?>
        <?php printf( __( '&copy;', 'jamedo-bootstrap-start-theme' )); ?> <?php echo date('Y');?> <?php echo bloginfo('name');?><span class="sep"> | </span><a target="_blank" href="https://wordpress.stackexchange.com/questions/135687/<?php esc_attr_e("http://www.jbst.eu/', 'jamedo-bootstrap-start-theme' ); ?>" title="https://wordpress.stackexchange.com/questions/135687/<?php esc_attr_e("Powered by JBST', 'jamedo-bootstrap-start-theme' ); ?>" rel="generator"><?php printf( __( 'Powered by JBST', 'jamedo-bootstrap-start-theme' ), 'jamedo-bootstrap-start-theme' ); ?></a>
    <?php }
}

add_action('jbst_credits', 'jbst_custom_credits');