Documentation: add "special refs" to the glossary

Add the "special refs" term to our glossary.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt
index f7d98c11e3dd0821094ae82cb488606a0de14732..d71b199955e15578c1392448cc5db0ce01240766 100644 (file)
--- a/Documentation/glossary-content.txt
+++ b/Documentation/glossary-content.txt
@@ -638,6 +638,20 @@ The most notable example is `HEAD`.
        An <<def_object,object>> used to temporarily store the contents of a
        <<def_dirty,dirty>> working directory and the index for future reuse.
 
+[[def_special_ref]]special ref::
+       A ref that has different semantics than normal refs. These refs can be
+       accessed via normal Git commands but may not behave the same as a
+       normal ref in some cases.
++
+The following special refs are known to Git:
+
+ - "`FETCH_HEAD`" is written by linkgit:git-fetch[1] or linkgit:git-pull[1]. It
+   may refer to multiple object IDs. Each object ID is annotated with metadata
+   indicating where it was fetched from and its fetch status.
+
+ - "`MERGE_HEAD`" is written by linkgit:git-merge[1] when resolving merge
+   conflicts. It contains all commit IDs which are being merged.
+
 [[def_submodule]]submodule::
        A <<def_repository,repository>> that holds the history of a
        separate project inside another repository (the latter of