diff --git a/plugin/transfer/README.md b/plugin/transfer/README.md
index a8d7b60fda35..c5b0d9a96c7b 100644
--- a/plugin/transfer/README.md
+++ b/plugin/transfer/README.md
@@ -10,6 +10,9 @@ plugins.
 This plugin answers zone transfers for authoritative plugins that implement
 `transfer.Transferer`.
 
+Transfer answers AXFR requests and IXFR requests with AXFR fallback if the
+zone has changed.
+
 *transfer* is not currently implemented by any plugins.
 
 ## Syntax