Merge branch 'kh/doc-datamodel' into seen

The gitdatamodel documentation page has been linked from a handful
of key documentaiton pages.

* kh/doc-datamodel:
  doc: datamodel: link to the glossary
  doc: glossary: link four of the terms to gitdatamodel(7)
  doc: git: link to the gitdatamodel(7) tutorial
  doc: git: list gitdatamodel(7) as a concept guide

Documentation/git.adoc

@@ -25,7 +25,8 @@ and full access to internals.
 See linkgit:gittutorial[7] to get started, then see
 linkgit:giteveryday[7] for a useful minimum set of
 commands.  The link:user-manual.html[Git User's Manual] has a more
-in-depth introduction.
+in-depth introduction.  See linkgit:gitdatamodel[7] if you want to
+learn about the data model and important terminology.
 
 After you mastered the basic concepts, you can come back to this
 page to learn what commands Git offers.  You can learn more about
@@ -469,7 +470,9 @@ Higher level SCMs may provide and manage additional information in the
 
 Terminology
 -----------
-Please see linkgit:gitglossary[7].
+Please see linkgit:gitglossary[7].  See linkgit:gitdatamodel[7] for a
+discussion of the core data model, which includes important terminology
+used throughout the documentation.
 
 
 Environment Variables
@@ -1201,8 +1204,9 @@ SEE ALSO
 --------
 linkgit:gittutorial[7], linkgit:gittutorial-2[7],
 linkgit:giteveryday[7], linkgit:gitcvs-migration[7],
-linkgit:gitglossary[7], linkgit:gitcore-tutorial[7],
+linkgit:gitglossary[7], linkgit:gitdatamodel[7],
-linkgit:gitcli[7], link:user-manual.html[The Git User's Manual],
+linkgit:gitcore-tutorial[7], linkgit:gitcli[7],
+link:user-manual.html[The Git User's Manual],
 linkgit:gitworkflows[7]
 
 GIT

Documentation/gitdatamodel.adoc

@@ -24,6 +24,8 @@ Git's core operations use 4 kinds of data:
 3. <<index,The index>>, also known as the staging area
 4. <<reflogs,Reflogs>>: logs of changes to references ("ref log")
 
+See linkgit:gitglossary[7] for a comprehensive terminology reference.
+
 [[objects]]
 OBJECTS
 -------
@@ -300,6 +302,10 @@ $ git reflog main --date=iso --no-decorate
 4ccb6d7 main@{2025-09-29 15:16:48 -0400}: commit (initial): Initial commit
 ----
 
+SEE ALSO
+--------
+linkgit:gitglossary[7]
+
 GIT
 ---
 Part of the linkgit:git[1] suite

Documentation/gitglossary.adoc

@@ -16,6 +16,7 @@ include::glossary-content.adoc[]
 
 SEE ALSO
 --------
+linkgit:gitdatamodel[7],
 linkgit:gittutorial[7],
 linkgit:gittutorial-2[7],
 linkgit:gitcvs-migration[7],

Documentation/glossary-content.adoc

@@ -251,7 +251,8 @@ for a more flexible and robust system to do the same thing.
 	as objects. The index is a stored version of your
 	<<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even
 	a third version of a working tree, which are used
-	when <<def_merge,merging>>.
+	when <<def_merge,merging>>. See "THE INDEX" in
+	linkgit:gitdatamodel[7] for details.
 
 [[def_index_entry]]index entry::
 	The information regarding a particular file, stored in the
@@ -290,7 +291,8 @@ This commit is referred to as a "merge commit", or sometimes just a
 [[def_object]]object::
 	The unit of storage in Git. It is uniquely identified by the
 	<<def_SHA1,SHA-1>> of its contents. Consequently, an
-	object cannot be changed.
+	object cannot be changed. See "OBJECTS" in
+	linkgit:gitdatamodel[7] for details.
 
 [[def_object_database]]object database::
 	Stores a set of "objects", and an individual <<def_object,object>> is
@@ -587,12 +589,17 @@ extended in the future:
 Different subhierarchies are used for different purposes. For example,
 the `refs/heads/` hierarchy is used to represent local branches whereas
 the `refs/tags/` hierarchy is used to represent local tags..
++
+See also "REFERENCES" in linkgit:gitdatamodel[7].
 
 [[def_reflog]]reflog::
 	A reflog shows the local "history" of a ref.  In other words,
 	it can tell you what the 3rd last revision in _this_ repository
 	was, and what was the current state in _this_ repository,
-	yesterday 9:14pm.  See linkgit:git-reflog[1] for details.
+	yesterday 9:14pm.
++
+See "REFLOGS" in linkgit:gitdatamodel[7] for a short explanation of the
+format. See linkgit:git-reflog[1] for details.
 
 [[def_refspec]]refspec::
 	A "refspec" is used by <<def_fetch,fetch>> and

command-list.txt

@@ -218,6 +218,7 @@ gitcli                                  userinterfaces
 gitcore-tutorial                        guide
 gitcredentials                          guide
 gitcvs-migration                        guide
+gitdatamodel                            guide
 gitdiffcore                             guide
 giteveryday                             guide
 gitfaq                                  guide