The robots.txt file is used by websites to tell bots which parts of their site need to be crawled and indexed. This standard is also known as the robots exclusion protocol. You can use this file to specify which areas of your site you don't want to be processed by crawlers, such as areas containing duplicate content or under development. However, not all bots follow this standard, so there's a chance that the bot will begin crawling your site from the areas you don't want to be indexed.