Local or Obsolete packages and upgrading Ubuntu

[Colin Law]

I am preparing to upgrade my Quantal system to Raring and following
the suggestions in [1] I have opened Synaptic Package Manager, clicked
on Status and selected Installed (local or obsolete) and expected to
see a short list of stuff I had installed from downloaded debs etc.
Instead I see a long list of packages including, for example
libcamel-1.2-33, libcamel-1.2-39, libcupsdriver1, libpoppler26, proj,
ubuntuone-installer, ubuntuone-control-panel-common and many more.

Does anyone know how these might have got there and whether I can
safely remove them?

Colin

[1] https://help.ubuntu.com/community/CleanUpgrade