Docs: more detail for DKIM

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index f99f86011e5860afb14f47318f145062bf9f58c0..1f5e295119726d9d868533f8a335e850e3bd75c6 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -42027,7 +42027,7 @@ option.
 
 .endlist
 
-In addition, two ACL conditions are provided:
+In addition, two ACL conditions are provided, usable only in a DKIM ACL:
 
 .vlist
 .vitem &%dkim_signers%&