diff --git a/intl/lwbrk/LineBreaker.cpp b/intl/lwbrk/LineBreaker.cpp
--- a/intl/lwbrk/LineBreaker.cpp
+++ b/intl/lwbrk/LineBreaker.cpp
@@ -451,10 +451,11 @@
       /* AKSARA = 43,                       [AK] */ CLASS_CHARACTER,
       /* AKSARA_PREBASE = 44,               [AP] */ CLASS_CHARACTER,
       /* AKSARA_START = 45,                 [AS] */ CLASS_CHARACTER,
       /* VIRAMA_FINAL = 46,                 [VF] */ CLASS_CHARACTER,
       /* VIRAMA = 47,                       [VI] */ CLASS_CHARACTER,
+      /* UNAMBIGUOUS_HYPHEN = 48            [HH] */ CLASS_BREAKABLE,
   };
 
   static_assert(U_LB_COUNT == std::size(sUnicodeLineBreakToClass),
                 "Gecko vs ICU LineBreak class mismatch");