uninstall.php

<?php
/**
 * File that is run during plugin uninstall (not just de-activate)
 *
 * @TODO: delete all tables in network if on multisite
 */

// If uninstall not called from WordPress exit.
if ( ! defined( 'WP_UNINSTALL_PLUGIN' ) ) {
	exit();
}

/*
Go on with uninstall actions:
 - Remove our database table
 - Remove options:
*/

// Remove options.
$arr_options = array(
	'simple_history_pager_size',
	'simple_history_db_version',
	'simple_history_rss_secret',
	'simple_history_show_on_dashboard',
	'simple_history_show_as_page',
);

foreach ( $arr_options as $one_option ) {
	delete_option( $one_option );
}

global $wpdb;

// Remove database tables.
$table_name = $wpdb->prefix . 'simple_history';
$wpdb->query( "DROP TABLE IF EXISTS $table_name" ); // PHPCS:ignore

$table_name = $wpdb->prefix . 'simple_history_contexts';
$wpdb->query( "DROP TABLE IF EXISTS $table_name" ); // PHPCS:ignore

// And we are done. Simple History is ... history.