Groups - as used in the System Browser's Packages pane

System Browser groups

These are just to help you group packages that you need in development.

They are different from groups in Metacello.

If you open the system browser "Nautilus":

in Pharo 4, there are three items at the top of the list of packages in the packages pane.
   Last Modified Classes.
   Most Viewed Classes and
   Work )
in Pharo 5 there are two types of item at the top of the list of packages in the packages pane.
   _____s, of which there is one
      Last Modified Methods
   Groups (of which there are two)
      Configurations
      Work

"Configurations" includes all the "ConfigurationOfXXX" packages. You don't usually want to see them in the list of code packages, as you'll use the System Browser for viewing and amending the code packages, and Versionner to amend and manage the Configuration packages, so they've been corralled into this category in the System Browser.

In an initial image the "Work" group is empty.

If you like you can put the package you are currently developing into this group.

Just right click on the "Work" tree node and select "Open group manager". You can put packages in or
create own custom groups for browsing code packages.

This means that when you're working on a package starting with a letter late in the alphabet, (like, say, "Zinc-HTTP") you are saved from having to scroll-down through the list of all packages to get to it, each time.  Instead, you can get to it in the Work group (or any other group you add it to), up at the top of the packages pane of the System Browser.