xorg from 1.0.1-9 to 1.0.1-9.fc5

[Gianluca Cecchi]

Running yum update today on my fc5 x86 system I see that it wants to
upgrade xorg-x11-server-Xorg from 1.0.1-9 to 1.0.1-9.fc5.
Quering the changelog of the proposed update rpm file, after simply
downloading it, I get:
* Mon Apr 10 2006 Ray Strode <rstrode at redhat.com> - 1.0.1-9.fc5
- Fix small overflow that causes crash on vt switch on ppc.
  Patch by David Woodhouse (bug 187083).

* Wed Mar 15 2006 Ray Strode <rstrode at redhat.com> - 1.0.1-9
- CVE-2006-0745 (bug 185084)

Is the "fc5" postfix to tell that the update is only needed for a
particular architecture or what does it mean? In that case why does
yum try to update it anyway on x86?
Wouldn't be better to name it 1.0.1-10?
Going through bug  187083 thread doesn't help me to understand the
"fc5" meaning....
Any pointer?
Thanks,
Gianluca