diff --git a/.github/workflows/xpkgindex-update.yml b/.github/workflows/xpkgindex-update.yml
index 6e26a37b..10ab13b4 100644
--- a/.github/workflows/xpkgindex-update.yml
+++ b/.github/workflows/xpkgindex-update.yml
@@ -26,6 +26,11 @@ concurrency:
 env:
   PYTHONUTF8: '1'
   MCPP_VERSION: '2026.10.26.1'
+  # CROSS-VALIDATION BEFORE A RELEASE: a candidate that needs an mcpp newer
+  # than the pin (its package states the floor) is built with mcpp built from
+  # this branch of mcpp-community/mcpp, as openkal-compat.yml measures with it.
+  # Empty in an ordinary run.
+  MCPP_SOURCE_REF: ${{ vars.MCPP_SOURCE_REF || '' }}
   MCPP_INDEX_MIRROR: GLOBAL
 
 jobs:
@@ -204,6 +209,19 @@ jobs:
           else
             echo "MCPP=$root/bin/mcpp" >> "$GITHUB_ENV"
           fi
+      - name: The mcpp under review, built from MCPP_SOURCE_REF when it is set
+        if: env.MCPP_SOURCE_REF != ''
+        shell: bash
+        run: |
+          src="$RUNNER_TEMP/mcpp-src"
+          git clone --quiet --depth 1 --branch "$MCPP_SOURCE_REF" https://github.com/mcpp-community/mcpp.git "$src"
+          rm -f "$src/.xlings.json"
+          ( cd "$src" && "$MCPP" build --release )
+          built=$(find "$src/target" -type f \( -name mcpp -o -name mcpp.exe \) -path '*/bin/*' | head -1)
+          [ -n "$built" ] || { echo "::error::mcpp did not build from $MCPP_SOURCE_REF"; exit 1; }
+          if [[ "$RUNNER_OS" == Windows ]]; then built=$(cygpath -m "$built"); fi
+          echo "MCPP=$built" >> "$GITHUB_ENV"
+          echo "under review: $("$built" --version)  (from $MCPP_SOURCE_REF)"
       - name: Install macOS ODBC development headers
         if: runner.os == 'macOS' && matrix.id == 'compat:nanodbc'
         run: brew install libiodbc
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bf63361f..99ec69e3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,6 +38,11 @@
   openkal-macos 0.15.1 与 openkal-windows 0.13.3,以 `KAL_SPAWN_ONE_STRING` 启动命令解释器的 image 在 okrun
   下得到该标志的语义;三个包仍为同一版本、同一归档。openkal-musl 随 openkal-windows 0.13.3 与 openkal-ld 0.1.1
   移动,openkal-llvm-runtime 随 openkal-musl 移动。测试成员 `openkal`、`openkal-musl`、`openkal-tools` 随之移动。
+- **mcpp.plugins 0.20.0。** 新特性 `plugins-platform`(模块 `mcpp.plugins.platform`):平台插件与包格式提供者的
+  `provide_format`(声明格式,并在请求该格式的一遍中由暂存包的 `mcpp-package.json` 生成 artifact action),以及平台的
+  链接、产物命名、封装与运行主机的带检查的写法(mcpp SPEC-013 协议 17);`mcpp::plugins::package` 读取暂存包的
+  `mcpp-package.json`(SPEC-014 §4.5)。SYCL 构建只有一个 C++ 运行时(libstdc++)。需要 mcpp 2026.10.27.1;
+  `latest` 仍指向 0.19.1,随 mcpp 2026.10.27.1 发布移动。
 - **openkal-platform 0.17.1(新包)。** ok 映像目标 `x86_64-openkal`、`aarch64-openkal` 的平台包(mcpp SPEC-013):
   工具链 llvm@23.1.3,C 库 openkal-musl 0.22.3,C++ 与编译器运行时 openkal-llvm-runtime 0.16.3,工具 okld、okrun
   (openkal-tools 0.1.1),编译与链接约定、封装、命名、运行器、载体,宿主组合与 openkal 0.17.1 的版本组。
diff --git a/pkgs/m/mcpp.plugins.lua b/pkgs/m/mcpp.plugins.lua
index a743165b..ae8d3c07 100644
--- a/pkgs/m/mcpp.plugins.lua
+++ b/pkgs/m/mcpp.plugins.lua
@@ -651,6 +651,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.20.0"] = {
+                url = {
+                    GLOBAL = "https://github.com/mcpp-community/mcpp-plugins/archive/refs/tags/v0.20.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/mcpp-plugins/releases/download/0.20.0/mcpp-plugins-0.20.0.tar.gz",
+                },
+                sha256 = "d216989adedc2df616e693a2ac908d5d37e4cbac9ad008bdcd5af685eedd34ac",
+            },
             ["0.19.1"] = {
                 url = {
                     GLOBAL = "https://github.com/mcpp-community/mcpp-plugins/archive/refs/tags/v0.19.1.tar.gz",
@@ -927,6 +934,13 @@ package = {
             ["latest"] = { ref = "0.19.1" },
         },
         macosx = {
+            ["0.20.0"] = {
+                url = {
+                    GLOBAL = "https://github.com/mcpp-community/mcpp-plugins/archive/refs/tags/v0.20.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/mcpp-plugins/releases/download/0.20.0/mcpp-plugins-0.20.0.tar.gz",
+                },
+                sha256 = "d216989adedc2df616e693a2ac908d5d37e4cbac9ad008bdcd5af685eedd34ac",
+            },
             ["0.19.1"] = {
                 url = {
                     GLOBAL = "https://github.com/mcpp-community/mcpp-plugins/archive/refs/tags/v0.19.1.tar.gz",
@@ -1203,6 +1217,13 @@ package = {
             ["latest"] = { ref = "0.19.1" },
         },
         windows = {
+            ["0.20.0"] = {
+                url = {
+                    GLOBAL = "https://github.com/mcpp-community/mcpp-plugins/archive/refs/tags/v0.20.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/mcpp-plugins/releases/download/0.20.0/mcpp-plugins-0.20.0.tar.gz",
+                },
+                sha256 = "d216989adedc2df616e693a2ac908d5d37e4cbac9ad008bdcd5af685eedd34ac",
+            },
             ["0.19.1"] = {
                 url = {
                     GLOBAL = "https://github.com/mcpp-community/mcpp-plugins/archive/refs/tags/v0.19.1.tar.gz",