diff --git a/source/compatibility.tex b/source/compatibility.tex
index fe9d4ce861..2e4d0d5bb6 100644
--- a/source/compatibility.tex
+++ b/source/compatibility.tex
@@ -401,6 +401,8 @@
 \rSec2[diff.cpp20.lex]{\ref{lex}: lexical conventions}
 
 \diffref{lex.name}
+\indextext{XID_Start}%
+\indextext{XID_Continue}%
 \change
 Previously valid identifiers containing characters
 not present in \UAX{44} properties XID_Start or XID_Continue, or
diff --git a/source/lex.tex b/source/lex.tex
index 021bda1ecc..6cf011e432 100644
--- a/source/lex.tex
+++ b/source/lex.tex
@@ -837,6 +837,8 @@
 \indextext{token|)}
 
 \rSec1[lex.name]{Identifiers}
+\indextext{XID_Start}%
+\indextext{XID_Continue}%
 
 \indextext{identifier|(}%
 \begin{bnf}
diff --git a/source/uax31.tex b/source/uax31.tex
index ee0bb9c2a1..44001f1346 100644
--- a/source/uax31.tex
+++ b/source/uax31.tex
@@ -18,6 +18,8 @@
 \rSec1[uaxid.def]{R1 Default identifiers}
 
 \rSec2[uaxid.def.general]{General}
+\indextext{XID_Start}%
+\indextext{XID_Continue}%
 
 \pnum
 \UAX{31} specifies a default syntax for identifiers