A fairly common question I see in the support forums is why is Google crawling my robots.txt file.
Today I spotted a thread from a webmaster in the Google Webmaster Help forums where Google was crawling the mobile version of the robots.txt file, which does not exist.
In short, it was trying to crawl /robots.txt?m=1. In this case, it is not really something this webmaster can control, being that he is on Google's Blogger system.
Here is a screen shot of the error:
Google's John Mueller told the webmaster he would relay the issue to the Blogger team but he doesn't need to worry. John wrote:
This can happen when you explicitly crawl the robots.txt with a smartphone Googlebot, such as you can do through Fetch as Google in Webmaster Tools, or such as what might happen if we try to crawl the robots.txt file for indexing (for example, if there's a link to it). We don't fetch the robots.txt file in that way for normal robots.txt processing, so that's not something you'd need to worry about. I agree it's a bit confusing (when trying to diagnose this kind of issue) when Blogger does that redirect for smartphone requests, so I'll pass that on to the team as feedback. Thanks!
Yes, these errors can get messy in Google Webmaster Tools.
Forum discussion at Google Webmaster Help.
Image credit to BigStockPhoto for 404 skull