Most comparisons points out the major differences, rather than all the ways they are the same.
As you can see from bullet point #5 from the fossil home page, it works offline:
> CGI/SCGI Enabled - No server is required, but if you want to set one up, Fossil supports four easy server configurations.
and #6 concerns later online merging:
> Autosync - Fossil supports "autosync" mode which helps to keep projects moving forward by reducing the amount of needless forking and merging often associated with distributed projects.
As you can see from bullet point #5 from the fossil home page, it works offline:
> CGI/SCGI Enabled - No server is required, but if you want to set one up, Fossil supports four easy server configurations.
and #6 concerns later online merging:
> Autosync - Fossil supports "autosync" mode which helps to keep projects moving forward by reducing the amount of needless forking and merging often associated with distributed projects.
There's also the quick start guide with an overview of distributed-ness - https://fossil-scm.org/fossil/doc/trunk/www/quickstart.wiki .