[R-sig-Debian] autoremove_

[Göran Broström]

When I upgraded my ubuntu 18.04 system today, I got to my surprise:

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goran using M6800:~$ sudo apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer 
required:
   littler r-cran-littler r-cran-pkgkitten
Use 'sudo apt autoremove' to remove them.
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(Why) should I remove them? Why are they 'no longer required'?

Göran