diff --git a/doc/config b/doc/config
index fbe078e..9068e64 100644
--- a/doc/config
+++ b/doc/config
@@ -70,8 +70,13 @@ Sections:
         %{track},
         %{year}.
       Untagged files or files in unrecognized formats will not be changed.
+      Surrounding a field with [] makes it optional, meaning renaming will still
+      happen if the corresponding tag is not defined.
     * fat32compat <yes>/<no>: Rename files for compatibility with FAT32
       filesystems.
+    * ascii-only <yes>/<no>: Rename files for compatibility with ASCII-only
+      systems. Uses Perl with Text::Unidecode to replace cyrillic or kanji
+      with an ASCII representation.
     * skip_mime-type <mime-type>: Files with mime-type <mime-type> will not
       be included in that destination. For more than one mime-type, use multiple
       times, as needed. The '*' character is a wildcard.
diff --git a/lib/setup/destination b/lib/setup/destination
index e9402a1..7293fbf 100644
--- a/lib/setup/destination
+++ b/lib/setup/destination
@@ -246,6 +246,8 @@ setupDestination() {
                 %{track},
                 %{year}.
             Untagged files or files in unrecognized formats will not be changed.
+            Surrounding a field with [] makes it optional, meaning renaming
+            will still happen if the corresponding tag is not defined.
 
             Leave blank if you don't want file renaming.
 	EODesc
@@ -298,6 +300,8 @@ setupDestination() {
         ASCII-only filenames (boolean):
             Rename files for compatibility with ASCII-only systems (most car
 	    radios).
+             Uses Perl with Text::Unidecode to replace cyrillic or kanji
+             with an ASCII representation.
 	EODesc
 	case ${destinationascii["$destination"]} in
 		0)	initialvalue=n		;;