-# This file is a supplement to the UnicodeData file.
-# It contains additional information about the casing of Unicode characters.
-# (For compatibility, the UnicodeData.txt file only contains case mappings for
-# characters where they are 1-1, and does not have locale-specific mappings.)
-# For more information, see the discussion of Case Mappings in the Unicode Standard.
+# Special Casing
+#
+# This file is a supplement to the UnicodeData.txt file. It does not define any
+# properties, but rather provides additional information about the casing of
+# Unicode characters, for situations when casing incurs a change in string length
+# or is dependent on context or locale. For compatibility, the UnicodeData.txt
+# file only contains simple case mappings for characters where they are one-to-one
+# and independent of context and language. The data in this file, combined with
+# the simple case mappings in UnicodeData.txt, defines the full case mappings
+# Lowercase_Mapping (lc), Titlecase_Mapping (tc), and Uppercase_Mapping (uc).
+#
+# Note that the preferred mechanism for defining tailored casing operations is
+# the Unicode Common Locale Data Repository (CLDR). For more information, see the
+# discussion of case mappings and case algorithms in the Unicode Standard.