I'm not a pc expert but understood it is a warning from your antivirus that the zip file is small and will extract to a huge file which might result in using up all your memory or it even might be a virus. If you google it you will see some comments on it and everybody seems to rather advise to delete and ignore it. Might be wrong in my understanding and would like to see more comments from the computer boffins on the site.

So can you tell us where - especially if it is one of our regular downloads?

It in the new monkey alpha, from berninablog.com
It is not a virus, it is just a very large file. The best that I understand. I extracted it and it was ok.