@item gnus-use-idna
This variable controls whether Gnus performs IDNA decoding of
internationalized domain names inside @samp{From}, @samp{To} and
-@samp{Cc} headers. This requires
+@samp{Cc} headers. @xref{IDNA, ,IDNA,message, The Message Manual},
+for how to compose such messages. This requires
@uref{http://www.gnu.org/software/libidn/, GNU Libidn}, and this
variable is only enabled if you have installed it.