Hi, if it is same download, then it is a generic archive file. Open with any unZipper, even XP's own.
I've had a look, it includes Mac and DS files which my
Poser cannot read, but that's a different issue.
A caution: Not all unZip programs are equal. Some have a 'run length' problem with OBJ and 3DS files created by other archivers. eg when my preferred IZArch cannot unpack Eric Saltel's mesh-archive files into valid models, I use QuickZip. Best to have several available...
And, yes, keep free IrfanView handy: Clicking on an unknown piccy file-type usually produces message "This is a mislabeled JPG: Rename ?".
When you get one of those, send Irfan a very kind 'thank you' for the rescue...