by a set of relational lookup tables for quick indexing into that
artifact store.  (See "[./theory1.wiki|Thoughts On The Design Of The
Fossil DVCS]" for more details.)

Leaf check-ins in Git that lack a "ref" become "detached," making them
difficult to locate and subject to garbage collection. This
[http://gitfaq.org/articles/what-is-a-detached-head.html|detached head
state] problem has caused untold grief for countless Git users. With
state] problem has caused untold grief for
[https://www.google.com/search?q=git+detached+head+state | a huge number
of Git users]. With
Fossil, detached heads are simply impossible because we can always find
our way back into the block chain using one or more of the relational
indices it automatically manages for you.

This design difference shows up in several other places within each
tool. It is why Fossil's [/help?cmd=timeline|timeline] is generally more
detailed yet more clear than those available in Git front-ends.