diff --git a/README.md b/README.md
index 5519e9a..3ff8991 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,8 @@
 # repo
 
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/README.md
+
 Repo is a tool built on top of Git.  Repo helps manage many Git repositories,
 does the uploads to revision control systems, and automates parts of the
 development workflow.  Repo is not meant to replace Git, only to make it
diff --git a/SUBMITTING_PATCHES.md b/SUBMITTING_PATCHES.md
index c51fac0..e02a753 100644
--- a/SUBMITTING_PATCHES.md
+++ b/SUBMITTING_PATCHES.md
@@ -1,3 +1,6 @@
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/SUBMITTING_PATCHES.md
+
 [TOC]
 
 # Short Version
diff --git a/docs/internal-fs-layout.md b/docs/internal-fs-layout.md
index 3537dfd..e9446ef 100644
--- a/docs/internal-fs-layout.md
+++ b/docs/internal-fs-layout.md
@@ -1,5 +1,8 @@
 # Repo internal filesystem layout
 
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/docs/internal-fs-layout.md
+
 A reference to the `.repo/` tree in repo client checkouts.
 Hopefully it's complete & up-to-date, but who knows!
 
diff --git a/docs/manifest-format.md b/docs/manifest-format.md
index 676e031..bdb0ee8 100644
--- a/docs/manifest-format.md
+++ b/docs/manifest-format.md
@@ -1,5 +1,8 @@
 # repo Manifest Format
 
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
+
 A repo manifest describes the structure of a repo client; that is
 the directories that are visible and where they should be obtained
 from with git.
diff --git a/docs/python-support.md b/docs/python-support.md
index a5c490a..f2062b4 100644
--- a/docs/python-support.md
+++ b/docs/python-support.md
@@ -1,5 +1,8 @@
 # Supported Python Versions
 
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/docs/python-support.md
+
 With Python 2.7 officially going EOL on [01 Jan 2020](https://pythonclock.org/),
 we need a support plan for the repo project itself.
 Inevitably, there will be a long tail of users who still want to use Python 2 on
diff --git a/docs/release-process.md b/docs/release-process.md
index 0df590a..170dbc2 100644
--- a/docs/release-process.md
+++ b/docs/release-process.md
@@ -1,5 +1,8 @@
 # repo release process
 
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/docs/release-process.md
+
 This is the process for creating a new release of repo, as well as all the
 related topics and flows.
 
diff --git a/docs/repo-hooks.md b/docs/repo-hooks.md
index 7c37c30..6c5eac3 100644
--- a/docs/repo-hooks.md
+++ b/docs/repo-hooks.md
@@ -1,5 +1,8 @@
 # repo hooks
 
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/docs/repo-hooks.md
+
 [TOC]
 
 Repo provides a mechanism to hook specific stages of the runtime with custom
diff --git a/docs/windows.md b/docs/windows.md
index 4282beb..7453188 100644
--- a/docs/windows.md
+++ b/docs/windows.md
@@ -1,5 +1,8 @@
 # Microsoft Windows Details
 
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/docs/windows.md
+
 Repo is primarily developed on Linux with a lot of users on macOS.
 Windows is, unfortunately, not a common platform.
 There is support in repo for Windows, but there might be some rough edges.
diff --git a/release/README.md b/release/README.md
index 3b81d53..7f3a5e9 100644
--- a/release/README.md
+++ b/release/README.md
@@ -1,2 +1,5 @@
+> **Warning: The "master" branch is no longer used.  Use "main" instead.**<br>
+> https://gerrit.googlesource.com/git-repo/+/HEAD/release/README.md
+
 These are helper tools for managing official releases.
 See the [release process](../docs/release-process.md) document for more details.