Recently, an update that caused a problem with Gnome session caused me to lose a day's work. The solution was to rollback some packages to a previous version.

The update manager is now telling me that my old packages should be updated:

... but I don't want to do that until I know that whatever bug or problem the latest version has is resolved.

I understand that with any upgrade that there is a risk of instability. However, in the 8 years or more that I've been on Ubuntu, using the latest releases has been stable enough and with the benefit of the latest features and security. So, I'm not looking for general advice on how to handle upgrades.

What I'm saying is that in this one particular instance, the bug introduced by these upgrades is severe and time wasting. But, as an end user, when I encounter a problem like this, I have no idea how to address a specific concern about a specific package. I don't, for example, know which of these packages is the problem, and I can't take time from my work schedule to be experimenting with each package.

So, my question is:

How do I find out who exactly is responsible for these, or any, packages so that I can contact them and let them know about the problem?

How do I freeze these packages only, but allow other upgrades to happen?

ubuntu-session
gnome-session-common
gnome-session-bin
gnome-session