Why does this zip file have a "_MACOSX" folder?

If you ever unzip a zip file to find something like the image below, the explanation is this: this file was originally zipped up using a Mac.

In the example above, assume that the folder called "Zip Folder" is the folder that was yielded from unzipping the zip file.  As you can see, inside that folder are two more folders:

1. "Zipped Files" - please note that "Zipped Files" is just an example.  Your unzipped folder will likely be called something else.
2. "_MACOSX" - this is a folder created by default whenever a Macintosh is used to create a zip file.

So now what?

1. The folder called _MACOSX is garbage.  It contains absolutely useless files.  Feel free to delete the _MACOSX folder and all the files contained in it.
2. The other folder ("Zipped Files" in the example above) has the files you're looking for.  Open that folder up and have a look.