Fossil

small and sometimes haphazard contributions.  Fossil
promotes a "cathedral" development model in which the project is
closely supervised by an highly engaged architect and implemented by
a clique of developers.

Nota Bene:  This is not to say that Git cannot be used for cathedral-style
development or that Fossil cannot be used for bazaar-style development.
They can be.  But those modes are not their design intent nor the their
low-friction path.

Git encourages a style in which individual developers work in relative
isolation, maintaining their
own branches and occasionally rebasing and pushing selected changes up
to the main repository.  Developers using Git often have their own
private branches that nobody else ever sees.  Work becomes siloed.

Git was specifically designed to support the development of Linux.
Fossil was specifically designed to support the development of SQLite.

Both SQLite and Linux are important pieces of software.
SQLite is found on far more systems than Linux.  (Almost every Linux
system uses SQLite, but there are many non-Linux systems such as
iPhones, PlayStations, and Windows PC that use SQLite.)  On the other
hand, for those systems that do use Linux, Linux is a far more important
component.

Linux uses a bazaar-style development model.  There are thousands and
thousands of contributors, most of whom do not know each others names.
Git is designed for this scenario.