How to tell which repositories provide which packages?

[Ralf Mardorf]

Another idea, only listing the package names and nothing else, assuming
the Ubuntu flavour installs are x86_64 only nowadays.

One package per line...

[weremouse at moonstudio ~]$ dpkg -l $(awk '$1 == "Package:" { print $2 }' /var/lib/apt/lists/*webupd8*amd64_Packages) 2>/dev/null | grep ii | awk '{print $2}' | sed 's/:amd64//g'
audacious
audacious-plugins
audacious-plugins-data
libampache-browser
libaudcore5
libaudgui5
libaudqt2
libaudtag3
python-twodict
youtube-dlg

...or all packages by one line

[weremouse at moonstudio ~]$ echo $(dpkg -l $(awk '$1 == "Package:" { print $2 }' /var/lib/apt/lists/*webupd8*amd64_Packages) 2>/dev/null | grep ii | awk '{print $2}' | sed 's/:amd64//g')
audacious audacious-plugins audacious-plugins-data libampache-browser libaudcore5 libaudgui5 libaudqt2 libaudtag3 python-twodict youtube-dlg