| BaseManifest | A complete index of what the site held at one instant, or the change since the last one. |
| BasePolicy | Decides when an anchor is due, and when it has to be a full one. |
| BaseReader | Reads an anchor back, and follows the chain until the index is complete. |
| BaseWriter | Writes the anchors a replay starts from. |
| Commit | One point in the site's history. |
| CommitIndex | A local index over the commits in the object store. |
| CommitLog | Reads and appends the history a restore walks. |
| RefStore | Holds the pointers that say where history currently ends. |
| SubjectIndex | Where every subject was last stored, kept locally so a flush reads nothing. |