[CentOS] CentOS-7-x86_64-GenericCloud.raw very unusual format

Hello!

Is anyone aware why CentOS-7-x86_64-GenericCloud.raw has such unusual format ?

root at test-srv:~# wget
http://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud.raw
--2016-03-21 13:16:31--
http://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud.raw
Resolving cloud.centos.org (cloud.centos.org)... 162.252.80.138
Connecting to cloud.centos.org
(cloud.centos.org)|162.252.80.138|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 374668382 (357M) [application/x-gzip]
Saving to: 'CentOS-7-x86_64-GenericCloud.raw'
CentOS-7-x86_64-GenericCloud.raw
100%[=========================================================================>]
357.31M  12.9MB/s    in 30s
2016-03-21 13:17:03 (11.9 MB/s) - 'CentOS-7-x86_64-GenericCloud.raw'
saved [374668382/374668382]

Download reports [application/x-gzip] for raw file

And indeed
root at test-srv:~# file CentOS-7-x86_64-GenericCloud.raw
CentOS-7-x86_64-GenericCloud.raw: gzip compressed data, last modified:
Sat Feb 27 02:14:37 2016, from Unix

Ok, lets uncompress:
root at test-srv:~# zcat -d CentOS-7-x86_64-GenericCloud.raw >
CentOS-7-x86_64-GenericCloud.a

And check again
root at test-srv:~# file CentOS-7-x86_64-GenericCloud.a
CentOS-7-x86_64-GenericCloud.a: POSIX tar archive (GNU)

Ok. it's a tar archive.

root at test-srv:~# tar -xf CentOS-7-x86_64-GenericCloud.a -v
CentOS-7-x86_64-GenericCloud-1602.raw

Now it's CentOS-7-x86_64-GenericCloud-1602.raw file which is indeed raw

What is the point to pack single raw file into the tar.gz and to name it raw ?
Or it's just a mistake ?

Thanks!