wp_ajax_search_install_plugins

function wp_ajax_search_install_plugins() {
	check_ajax_referer( 'updates' );

	$pagenow = isset( $_POST['pagenow'] ) ? sanitize_key( $_POST['pagenow'] ) : '';
	if ( 'plugin-install-network' === $pagenow || 'plugin-install' === $pagenow ) {
		set_current_screen( $pagenow );
	}

	/** @var WP_Plugin_Install_List_Table $wp_list_table */
	$wp_list_table = _get_list_table(
		'WP_Plugin_Install_List_Table',
		array(
			'screen' => get_current_screen(),
		)
	);

	$status = array();

	if ( ! $wp_list_table->ajax_user_can() ) {
		$status['errorMessage'] = __( 'Sorry, you are not allowed to manage plugins for this site.' );
		wp_send_json_error( $status );
	}

	// Set the correct requester, so pagination works.
	$_SERVER['REQUEST_URI'] = add_query_arg(
		array_diff_key(
			$_POST,
			array(
				'_ajax_nonce' => null,
				'action'      => null,
			)
		),
		network_admin_url( 'plugin-install.php', 'relative' )
	);

	$wp_list_table->prepare_items();

	ob_start();
	$wp_list_table->display();
	$status['count'] = (int) $wp_list_table->get_pagination_arg( 'total_items' );
	$status['items'] = ob_get_clean();

	wp_send_json_success( $status );
}