13 branch is in early development

static/build.html

@@ -337,6 +337,9 @@
                         3a / Pixel 3a XL use the <code>12.1-crosshatch</code> branch setting an
                         appropriate <code>BUILD_ID</code> and security patch level field.</p>
 
+                        <p>The <code>13</code> branch is in early development and will be the
+                        branch used for all non-legacy devices.</p>
+
                         <pre>mkdir grapheneos-12.1
 cd grapheneos-12.1
 repo init -u https://github.com/GrapheneOS/platform_manifest.git -b 12.1