I think it's less about immutability and more about visibility. The argument made by the Fossil project, AFAIU, is that it has a better log view than git and h

I think it's less about immutability and more about visibility. The argument made by the Fossil project, AFAIU, is that it has a better log view than git and has better traceability through SQL based search in addition t the cli and web interface. What kind of note are you using? There are several and, if I recall correctly, that affects the view a bit. See the "Auxiliary notes attached to check-ins or branches" https://fossil-scm.org/home/doc/trunk/www/wikitheory.wiki https://fossil-scm.org/home/doc/trunk/www/wikitheory.wiki To me, associating a wiki page to a commit makes way more sense than as a commit message that's part of the commit. This way the message can give a summary and then the detail is given in full-fledged markup file that has its own version history. Totally fair if that's not something that works for you, though.