Questions about package handling in Unstable vs. Experimental

[info at bandshed.net]

Hi,

I am a little confused on the destination of packages etc during a Stable
freeze. Lives 1.3.10 was just released and according to the log at Debian
GIT it was placed in experimental...conversely Openshot Video Editor 1.2.1
was just released today and has entered Sid. I have both pegged for
inclusion in the next AV Linux release but I can't seem to find the 1.3.10
version of Lives in Debian experimental, I just built Lives 1.3.9 a few
days ago with no issues from GIT but 1.3.10 from GIT fails to build with
OSC errors which I will investigate further.

Finally is it normal for Sid to disappear from the Graphical "Software
Sources" even if it is still present in /etc/apt/sources.list?

Your patience and reply are appreciated,

-GLEN