to the result.
[[def_ref]]ref::
- A 40-byte hex representation of a <<def_SHA1,SHA-1>> or a name that
- denotes a particular <<def_object,object>>. They may be stored in
- a file under `$GIT_DIR/refs/` directory, or
- in the `$GIT_DIR/packed-refs` file.
+ A name that begins with `refs/` (e.g. `refs/heads/master`)
+ that points to an <<def_object_name,object name>> or another
+ ref (the latter is called a <<def_symref,symbolic ref>>).
+ For convenience, a ref can sometimes be abbreviated when used
+ as an argument to a Git command; see linkgit:gitrevisions[7]
+ for details.
+ Refs are stored in the <<def_repository,repository>>.
++
+The ref namespace is hierarchical.
+Different subhierarchies are used for different purposes (e.g. the
+`refs/heads/` hierarchy is used to represent local branches).
++
+There are a few special-purpose refs that do not begin with `refs/`.
+The most notable example is `HEAD`.
[[def_reflog]]reflog::
A reflog shows the local "history" of a ref. In other words,