how did that sneak in?

.vscode/extensions.json

@@ -2,9 +2,8 @@
     // See http://go.microsoft.com/fwlink/?LinkId=827846
     // for the documentation about the extensions.json format
     "recommendations": [
-        "platformio.platformio-ide"
+        "ms-vscode.cpptools",
+        "platformio.platformio-ide",
+        "trunk.io"
     ],
-    "unwantedRecommendations": [
-        "ms-vscode.cpptools-extension-pack"
-    ]
 }