When I get an update via update-manager for a software like blender/vlc,
I like to see what has been fixed/changed.

I added the ppa for blender/vlc (this only applies to the software I added a ppa for)

sudo add-apt-repository ppa:cheleb/blender-svn
sudo apt-get update
sudo apt-get install blender

And vlc like this.

sudo add-apt-repository ppa:videolan/stable-daily
sudo apt-get update
sudo apt-get install vlc

And when i run update-manager, or update manager pop-ups
I see that vlc/blender have updates but, I can't see what has been changed/fixed

this is the message I get, the screenshot below is for mupen but it's the same thing.
(I updated vlc and blender, didn't wanna wait for the next update)

This update does not come from a source that supports changelogs.

(by the way I have a dutch Ubuntu, so the above text i Google translated it!)
It only shows which version you have and to which version you be upgrading to.

So my question is, how do I get the change-log tab of update-manager working. if it's even possible?