Copying of web pages by Firefox

[Dr Sian Mountbatten <poenikatu@operamail.com>]

Someone in another group had a web-page in a Usenet newsgroup
article which I clicked on. KDE loaded firefox (which is my
default browser), but instead of giving me the web page, it
copied the web-page of the link into
/var/tmp/kdecache-sian/krun/13950.0.iu.html
Unfortunately, most of the links in the page are reference a file
in /var/tmp/kdecache-sian/krun/ which I do not have.

How can I prevent Firefox copying the web-page? And why does it
do it?

I might note that the newsgroup is soc.culture.esperanto and the
web page is in Esperanto using UTF-8.