Add some short documentation about the local manifest
Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/docs/manifest-format.txt b/docs/manifest-format.txt
index a84aa87..409524b 100644
--- a/docs/manifest-format.txt
+++ b/docs/manifest-format.txt
@@ -124,3 +124,32 @@
remotes are fetched from first on the initial `repo sync`, causing
the majority of the project's object database to be obtained through
these additional remotes.
+
+
+Local Manifest
+==============
+
+Additional remotes and projects may be added through a local
+manifest, stored in `$TOP_DIR/.repo/local_manifest.xml`.
+
+For example:
+
+----
+ $ cat .repo/local_manifest.xml
+ <?xml version="1.0" encoding="UTF-8"?>
+ <manifest>
+ <project path="manifest"
+ name="tools/manifest" />
+ <project path="platform-manifest"
+ name="platform/manifest" />
+ </manifest>
+----
+
+Users may add projects to the local manifest prior to a `repo sync`
+invocation, instructing repo to automatically download and manage
+these extra projects.
+
+Currently the only supported feature of a local manifest is to
+add new remotes and/or projects. In the future a local manifest
+may support picking different revisions of a project, or deleting
+projects specified in the default manifest.