Merge branch 'stable-3.9'

* stable-3.9:
  Explain on the about page when the code-owners plugin should/shouldn't be used

Change-Id: Idc42bb5c0ee0d445fab631f02e237771eed69f87
Reviewed-on: https://gerrit-review.googlesource.com/c/plugins/code-owners/+/409499
Tested-by: Zuul <zuul-63@gerritcodereview-ci.iam.gserviceaccount.com>
Reviewed-by: Nitzan Gur-Furman <nitzan@google.com>

resources/Documentation/about.md

diff --git a/resources/Documentation/about.md b/resources/Documentation/about.md
index fecbc41..1db9847 100644
--- a/resources/Documentation/about.md
+++ b/resources/Documentation/about.md
@@ -8,6 +8,12 @@
 
 An overview of the supported features can be found [here](feature-set.html).
 
+**IMPORTANT:** Using the @PLUGIN@ plugin is recommended only for repositories
+that contain files / folders that are owned by different users. If this is not
+the case, and all files / folders in the repository are owned by the same users
+[plain Gerrit permissions should be preferred
+instead](config-guide.html#configureCodeOwnersByPermissions).
+
 **IMPORTANT:** Before installing/enabling the plugin, or enabling the code
 owners functionality for further projects, follow the instructions from the
 [setup guide](setup-guide.html).