Add explanation of P3176

content/oxford-variadic-comma.md

@@ -0,0 +1,28 @@
+---
+execute: false
+---
+
+## What It Does
+
+This proposal makes use of a variadic ellipsis (`...`) deprecated,
+if it is not separated by a comma from previous parameters.
+
+## Why It Matters
+
+Without a separating comma,
+users can confuse whether `...` refers to a parameter pack
+or to "C-style" variadic arguments.
+The lack of a comma also prevents using syntax such as `int...` for new features,
+without changing the meaning of existing code.
+
+## Example
+
+```cpp
+void f(int...);        // deprecated
+void g(int, ...);      // OK, also valid in C
+void h(...);           // OK, also valid in C
+
+void i(auto...);       // OK, declares a function parameter pack
+void j(auto......);    // deprecated
+void k(auto..., ...);  // OK
+```

features_cpp26.yaml

@@ -909,6 +909,8 @@ features:
   - desc: "The Oxford variadic comma"
     paper: P3176
     support: [GCC 15, Clang 20]
+    summary: "Variadic ellipsis parameters (`...`) without a separating comma are deprecated, such as `int...`."
+    content: oxford-variadic-comma.md
 
   - desc: "Retiring niebloids"
     paper: P3136