[CentOS] Ques about 5 vs. 3 in CentOS-announce Digest, Vol 35, Issue 9

I don't know if I'm brain damaged this A.M. or what, but I can't figure
(recall?) why this summary says CentOS 5 in the "Today's Topics", has
"el5" and "centos.3" as well in the md5sum.

Gentle chides for being dense this morning are accepted.

TIA

-- 
Bill