1 files changed, 6 insertions, 2 deletions

diff --git a/docs/manifest-format.md b/docs/manifest-format.md
index bcdf5a8e..edcb28cb 100644
--- a/docs/manifest-format.md
+++ b/docs/manifest-format.md
@@ -125,8 +125,9 @@ following DTD:
   <!ATTLIST contactinfo bugurl  CDATA #REQUIRED>
 
   <!ELEMENT include EMPTY>
-  <!ATTLIST include name   CDATA #REQUIRED>
-  <!ATTLIST include groups CDATA #IMPLIED>
+  <!ATTLIST include name     CDATA #REQUIRED>
+  <!ATTLIST include groups   CDATA #IMPLIED>
+  <!ATTLIST include revision CDATA #IMPLIED>
 ]>
 ```
 
@@ -553,6 +554,9 @@ in the included manifest belong. This appends and recurses, meaning
 all projects in included manifests carry all parent include groups.
 Same syntax as the corresponding element of `project`.
 
+Attribute `revision`: Name of a Git branch (e.g. `main` or `refs/heads/main`)
+default to which all projects in the included manifest belong.
+
 ## Local Manifests {#local-manifests}
 
 Additional remotes and projects may be added through local manifest