I have found what may be a possible bug in the handling of private branches, or it may be that I am misunderstanding the way Fossil works.
If I clone a repository which contains some private branches, the timeline on the clone does not show all checkins, even those on a non-private node.
Here is a test repository that shows the problem:
(about 128kB)
Download the file.
Set it up as a server.
Clone the server into another fossil. (use "test" as both the user name and password)
View the timeline on both repositories. Some public checkins are missing on the clone.
The server and clone was generated using fossil version 1.21 46c27e29e3 2011-11-28 05:31:32 UTC
UPDATE: This bug has now been fixed by D Richard Hipp in fossil version 8d155c5f1f 2011-11-30 17:26:36 UTC