From the user's perspective, a group and profile have block content, as the Group Home or Profile Home. This is currently achieved by referencing a document from the group content using the / entry in the paths, and by referencing a profile home in the profile.rootDocument field.
This results in extra blobs being created when changing these home documents. An even bigger artifact of this issue is that there are two histories. You can navigate the history of the group+account, which may have a similar (or not!) history when compared to the history of the home document itself.