[Kiwix-developer] On Linux, why does Kiwix has the index file already?

[<xiw...@9o...>]

I downloaded the Wikipedia zip file (
http://download.kiwix.org/portable/wikipedia_en_all.zip
<http://s.bl-1.com/h/6wKt9mQ?url=http://download.kiwix.org/portable/wikipedia_en_all.zip>)
and unzipped it. There is an index folder with a file inside it. When I
load up the wikipedia zim inside my Linux Kiwix, Kiwix still asks me if I
want to index Wikipedia. But why would it do that if I already have the
index file?