BTW: There are probably only a few programs that need to be updated, so there is not really a pressing reason to use apt-get to do it rather than Application Manager. For most purposes, that's what it looks to me like Application Manager IS -- a graphical substitute for apt-get.

If only they had a checkbox for "upgrade everything possible", there would not even be a strong temptation to use apt-get, though I have appreciated the impetus to get "under the hood", to continue a metaphorical comparison between cars and tablets now ongoing in another thread...

And my understanding about those error messages about missing public keys is that they are basically not important, no? Si?