Register custom meta boxes for the 'testimony' archive settings

sample.php

<?php
/**
 * Register custom meta boxes for the 'testimony' archive settings.
 */
 
add_action( 'genesis_cpt_archives_settings_metaboxes' , 'cpt_as_testimony_archive_metaboxes' );
/**
 * Callback for Genesis 'genesis_cpt_archives_settings_metaboxes' action.
 *
 * Register custom meta boxes for the 'testimony' archive settings.
 *
 * @uses add_meta_box()
 * @see https://codex.wordpress.org/Function_Reference/add_meta_box
 *  
 * @global $_genesis_admin_cpt_archives_testimony Genesis_Admin_CPT_Archive_Settings object for the 'testimony' post type.
 *
 * @since 0.0.1
 * 
 * @param  string $pagehook The current page hook.
 * @return void
 */
function cpt_as_testimony_archive_metaboxes( $pagehook ) {

    global $_genesis_admin_cpt_archives_testimony;

    //* ensure we are on the correct archive settings page.
    if ( $pagehook !== $_genesis_admin_cpt_archives_testimony->pagehook ) {
        return;
    }

    add_meta_box(
        'cpt_as_testimony_posts_per_page_metabox',
        __( 'Testimony Extras', 'genesis-custom-post-type-archive-sample' ),
        'cpt_as_display_archive_settings_posts_per_page_box',
        $pagehook,
        'main'
    );

}