diff --git a/docs/manifest-format.txt b/docs/manifest-format.txt
index 7778409..0e6cbe3 100644
--- a/docs/manifest-format.txt
+++ b/docs/manifest-format.txt
@@ -47,6 +47,7 @@
     <!ATTLIST default sync-j      CDATA #IMPLIED>
     <!ATTLIST default sync-c      CDATA #IMPLIED>
     <!ATTLIST default sync-s      CDATA #IMPLIED>
+    <!ATTLIST default sync-tags   CDATA #IMPLIED>
 
     <!ELEMENT manifest-server EMPTY>
     <!ATTLIST manifest-server url CDATA #REQUIRED>
@@ -63,6 +64,7 @@
     <!ATTLIST project groups      CDATA #IMPLIED>
     <!ATTLIST project sync-c      CDATA #IMPLIED>
     <!ATTLIST project sync-s      CDATA #IMPLIED>
+    <!ATTLIST default sync-tags   CDATA #IMPLIED>
     <!ATTLIST project upstream CDATA #IMPLIED>
     <!ATTLIST project clone-depth CDATA #IMPLIED>
     <!ATTLIST project force-path CDATA #IMPLIED>
@@ -170,6 +172,10 @@
 
 Attribute `sync-s`: Set to true to also sync sub-projects.
 
+Attribute `sync-tags`: Set to false to only sync the given Git
+branch (specified in the `revision` attribute) rather than
+the other ref tags.
+
 
 Element manifest-server
 -----------------------