Flagging any zipfile that contains a javascript file in it seems over-the-top aggressive. That would flag pretty-much any Kobo kepub book.
I can't speak as to what that file actually is, but regardless ... that particular heuristic test wasn't thought out very well.
And in my personal opinion/experience: between calibre and antivirus software ... the antivirus software loses (at least when calibre is downloaded from official locations).