I have numerous little SEO Experiments constantly running at all times.
One of those little experiments is a page of HTML code saved as a text file with a .txt file extension – http://www.sim64.co.uk/serps-competition.txt
Until recently Google has realised that it is a HTML page and converted it in to a HTML page and displayed the HTML version of the page in the Google Cache.
On checking today, the Google cache is now displaying the text version of the page.
Has Google changed the way it reads text files?