The terms face group (in Analyzer) and pose group (in Retargeter) refer to the separate groups of the Eyes, Brows, and Mouth that are worked on separately during tracking and retargeting. Newer versions of the software include advanced options for a Jaw group and a Cheeks group.
In Analyzer, there is a Face face group, but it is not used for manual tracking, only for AutoTracking or checking the final tracking data for the whole face.
In Retargeter 4.6+, newly created character setup xml files will include a Head group by default for use with head rotation. There is no Head group in Analyzer, however, as the software takes the head rotation information directly from the other markup groups.