GitHub and download zip are different for 2.2.1?

cocos2d-x C++
#1

I cloned from github https://github.com/cocos2d/cocos2d-x.git and download zip from http://cdn.cocos2d-x.org/cocos2d-x-2.2.1.zip.
But I found contents in tag:cocos2d-x-2.2.1 are different from cocos2d-x-2.2.1.zip.
What’s up?

#3

There are different branches. Eg: master、develop and so on.