Using robots.txt - Webmaster. Help
https://yandex.com/support/webmaster/controlling-robot/robots-txt.html
Yandex robots correctly process robots.txt, if: The file size doesn't exceed 500 KB. It is a TXT file named "robots", robots.txt. The file is located in the root directory of the site.
Robots.txt File [2021 Examples] - Moz
https://moz.com/learn/seo/robotstxt
Robots.txt is a text file webmasters create to instruct web robots (typically search engine robots) how to The REP also includes directives like meta robots, as well as page-, subdirectory-, or site-wide...
Robots exclusion standard - Wikipedia
https://en.wikipedia.org/wiki/Robots_exclusion_standard
The robots exclusion standard, also known as the robots exclusion protocol or simply robots.txt, is a standard used by websites to communicate with web crawlers and other web robots.