Unknow .html file download. What is this?

I’m new to the forum but already a Sailfish OS user for 2 years now!
However I don’t have any programming skills FYI.
I noticed an unusual behaviour and I would like to know if it is normal.
From time to time - every other month or so - it automatically downloads an html file.
This sunday it downloaded the file Z7ro4Ycn.html. Searching the web I can´t seem to find anything about it.
Can you please help me to figure it out? What is this file for?
And if it is not important, how can I prevent it from downloading again?