diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,9 @@
+
+# Version 0.20.1.0 (2026-09-01)
+
+- Add `cTupleTyConName` and `isCTupleTyConName` to the export list of
+  `GHC.Builtins`.
+
 # Version 0.20.0.0 (2026-09-01)
 
 - Preliminary support for GHC 10.2 (with the known-entities refactor).
diff --git a/ghc-tcplugin-api.cabal b/ghc-tcplugin-api.cabal
--- a/ghc-tcplugin-api.cabal
+++ b/ghc-tcplugin-api.cabal
@@ -1,6 +1,6 @@
 cabal-version:  3.0
 name:           ghc-tcplugin-api
-version:        0.20.0.0
+version:        0.20.1.0
 synopsis:       An API for type-checker plugins.
 license:        BSD-3-Clause
 build-type:     Simple
diff --git a/src/GHC/Builtins.hs b/src/GHC/Builtins.hs
--- a/src/GHC/Builtins.hs
+++ b/src/GHC/Builtins.hs
@@ -85,6 +85,7 @@
     -- * Tuples and sums
   , tupleTyCon, tupleDataCon, promotedTupleDataCon
   , sumTyCon, sumDataCon
+  , cTupleTyConName, isCTupleTyConName
   , mkTupleTy, mkBoxedTupleTy, mkSumTy
   , mkListTy, mkPromotedListTy
 #if MIN_VERSION_ghc(8,10,0)