Seems the nightly builds miss a real changelog.
Seems that "news" file, has a tiny list of changes since 2.4 release (calliing it "Changes in VICE 3.0" which I am not sure it will ever come), but nothing really to detail not all the builds of course (not that it would be bad), but at least all the 2.4.X milestones (currently in 2.4.31 at the time of this ticket).
Why?
because that would require someone to maintain it, and pretty much noone would read it anyway.
if you really want to know what changed, you could look it up in the SVN history/log
The changelog is maintained, it's just not present in the bin dists, because it details the source code changes. Download the source tarball and you'll find the ChangeLog file(s) in the tarball.