Header Content-Type: txt

In my Argo content breakdown “txt” has lots of request (750k / 43%) but I’m unsure what these could be as ‘html’ and ‘css’ etc are listed separately.

Can anyone enlighten me?

Also, are the ‘empty’ requests generally just requests without a response…like 304 etc?

Thanks

Could it be the robots.txt? Since all crawlers do request it, high request rates are to be expected at that file.