Info about updates

Hi,

Where and how one can find addition information (like bugfix,
security,  update etc) about packages from updates with help yum API?
I'm interesting in the CentOS 6.5, 6.6 and 7.

I found that there is yum-plugin-security but it does not work well
for 6.5 and 6.6.  I have already seen the code of UpdateinfoCommand
from /usr/share/yum-cli/yumcommands.py . That code is hard to
understand.  May be there are simple code examples ?

-- 
Best regards, Maksim A. Boyko