[pdw]

Git is the same, if you rebase many hashes will be recalculated, and the "tampering" would be obvious to anyone who had a copy of the repository. It is possible to implement the equivalent of rebase in any distributed VCS, the authors of Fossil simply chose not to. If it becomes more popular, somebody else likely will.

[sgbeal]

i've been on the fossil dev team since 2008, and i have seen many people claim that it "could" be compromised/modified post facto, and yet... nobody has been able to do it. Fossil's core data model does not just _assume_ that history doesn't change - it makes it essentially impossible to do.

Shunning is a special case which removes a given artifact from the db, but is considered a "nuclear option" of last resort. i've never personally used it.