Hidden Resource in Robots.txt
The robots.txt file specifies how to inform the web robot about which areas of the website should not be processed or scanned. Robots are often used by search engines to categorize websites. Not all robots cooperate with the standard; email harvesters, spambots, malware, and robots that scan for security vulnerabilities may even start with the portions of the website where they have been told to stay out. Wikipedia
Do not reveal paths in robots.txt file.