An <<def_object,object>> which is not <<def_reachable,reachable>> from a
<<def_branch,branch>>, <<def_tag,tag>>, or any other reference.
+ The default <<def_branch,branch>> that is merged into the branch in
+ question (or the branch in question is rebased onto). It is configured
+ via branch.<name>.remote and branch.<name>.merge. If the upstream branch
+ of 'A' is 'origin/B' sometimes we say "'A' is tracking 'origin/B'".
The tree of actual checked out files. The working tree is
normally equal to the <<def_HEAD,HEAD>> plus any local changes