Forced Update of catindex.txt

Dear Xara...

I happened to have a catindex.txt file loaded as a document in Notepad++.
When I re-opened this application, it advised that catindex.txt had been changed and would I like to reload.

I took a snapshot of before and after to find all that had changed was the MS Windows modification date.
Also the catindex.old date had changed as well.
In both cases, neither files' contents had changed.

I consider this an intrusion. It might be that all the Xara Desktop application can do is delete a file and download a new one.
How often does this occur as I did not request it?
How can I change the frequency of this happening?
Can I prevent it happening?
Do actual revisions remove downloaded content from my machine?
Will you explain the mechanism that causes this and its possible flows?
Does this impact my Xara Desktop application that is not in Update service cover?

Acorn