file extensions supported

[bombayboyzone]

what file extensions are supported for offline installation of apps? like I know .apk is a supported file. Some websites upon download gives back a rar file and upon extraction there are a host of files. So how do we install these?

 

[Salakala]

it seems to me that .apk is just a container. It's just a zipped file with a .apk extension. After all android is just unix