diff --git a/doc/plugins/po.mdwn b/doc/plugins/po.mdwn
index 93ece9fb9..dddb46fc8 100644
--- a/doc/plugins/po.mdwn
+++ b/doc/plugins/po.mdwn
@@ -264,6 +264,11 @@ in the backlinks.
 
 `po_link_to = current`: seems to work nicely
 
+### parentlinks
+
+When `usedirs` is disabled and the home page is translatable, the
+parent link to the wiki home page is broken (`/index.html`).
+
 Translation quality assurance
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