What Is the robots.txt File and How Do You Create One?
5 Free Robots.txt Checker Websites
Robots.txt Validator Tool - LXRMarketplace Blog
Check robots.txt file of a website for errors and typos
Blocked or not? Wildcards, typos and other robots.txt ambiguities | TechnicalSEO.com
GitHub - nickmoline/robots-checker: Library to check a url for all possible robots exclusion protocols (robots.txt, http X-Robots-Tag header, meta robots tag, or http status codes)