diff --git a/mercurial/debugcommands.py b/mercurial/debugcommands.py
--- a/mercurial/debugcommands.py
+++ b/mercurial/debugcommands.py
@@ -4085,7 +4085,7 @@
     should complete almost instantaneously and the chances of a consumer being
     unable to access the repository should be low.
 
-    By default, all revlog will be upgraded. You can restrict this using flag
+    By default, all revlogs will be upgraded. You can restrict this using flags
     such as `--manifest`:
 
       * `--manifest`: only optimize the manifest