[CentOS] [EL6] How to follow upstream updates?

Thu Jan 26 21:35:15 UTC 2017
Leon Fauster <leonfauster at googlemail.com>

Sorry, if it was answered already elsewhere. 

Where exactly are the current EL6 builds done? 
Or rephrased: I would like to look into the state 
of following security update:

 mysql-5.1.73-8.el6_8.src.rpm

Looking into

 https://git.centos.org/repositories/ 
 http://cbs.centos.org 
 http://buildlogs.centos.org/

shows mostly EL7 stuff. 

Just curious,
LF