I'm having some trouble getting an understanding and visibility into the content history of the files managed by my git annex repository. `git log` shows changes to the files, but these changes are essentially just symlink changes. `git log -p` reveals these changes as symlink changes under `.git/annex`. What I want is: 1. Of a file, to see the changes to that file's content that have happened over time. 2. Of a file, to be able to revert it to an older version of that file's content. 3. Of a file, to get visibility into what versions of that file's content are available on what remotes.