This window gives quick access to all the group tags available to you. In other words, for each group, it shows the various tags which the group owner has enabled for you. This makes it easy to select one to activate.
The tags are shown in columns, along with the group it is associated with. Click the column header to sort.
The circular arrow will refresh the list.
Click Info to open the group profile, and Activate to set that group and tag active.