diff --git a/.appveyor.yml b/.appveyor.yml
index 85445d41a2..70328fe643 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -1,4 +1,7 @@
 version: 1.0.{build}
+branches:
+  only:
+    - will_not_exist_ever
 image:
 - Visual Studio 2015
 test: off
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 03c9225c12..1dd4d32027 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -10,472 +10,13 @@ on:
       - v*
 
 jobs:
-  # This is the "main" test suite, which tests a large number of different
-  # versions of default compilers and Python versions in GitHub Actions.
-  standard:
-    strategy:
-      fail-fast: false
-      matrix:
-        runs-on: [ubuntu-latest, windows-latest, macos-latest]
-        python:
-        - 2.7
-        - 3.5
-        - 3.6
-        - 3.9
-        - 3.10-dev
-        - pypy2
-        - pypy3
-
-        # Items in here will either be added to the build matrix (if not
-        # present), or add new keys to an existing matrix element if all the
-        # existing keys match.
-        #
-        # We support three optional keys: args (both build), args1 (first
-        # build), and args2 (second build).
-        include:
-          # Just add a key
-          - runs-on: ubuntu-latest
-            python: 3.6
-            args: >
-              -DPYBIND11_FINDPYTHON=ON
-          - runs-on: windows-latest
-            python: 3.6
-            args: >
-              -DPYBIND11_FINDPYTHON=ON
-
-        # These items will be removed from the build matrix, keys must match.
-        exclude:
-            # Currently 32bit only, and we build 64bit
-          - runs-on: windows-latest
-            python: pypy2
-          - runs-on: windows-latest
-            python: pypy3
-
-          # TODO: PyPy2 7.3.3 segfaults, while 7.3.2 was fine.
-          - runs-on: ubuntu-latest
-            python: pypy2
-
-    name: "🐍 ${{ matrix.python }} • ${{ matrix.runs-on }} • x64 ${{ matrix.args }}"
-    runs-on: ${{ matrix.runs-on }}
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup Python ${{ matrix.python }}
-      uses: actions/setup-python@v2
-      with:
-        python-version: ${{ matrix.python }}
-
-    - name: Setup Boost (Linux)
-      if: runner.os == 'Linux'
-      run: sudo apt-get install libboost-dev
-
-    - name: Setup Boost (macOS)
-      if: runner.os == 'macOS'
-      run: brew install boost
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v1.9
-
-    - name: Cache wheels
-      if: runner.os == 'macOS'
-      uses: actions/cache@v2
-      with:
-        # This path is specific to macOS - we really only need it for PyPy NumPy wheels
-        # See https://github.com/actions/cache/blob/master/examples.md#python---pip
-        # for ways to do this more generally
-        path: ~/Library/Caches/pip
-        # Look to see if there is a cache hit for the corresponding requirements file
-        key: ${{ runner.os }}-pip-${{ matrix.python }}-x64-${{ hashFiles('tests/requirements.txt') }}
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
-
-    - name: Setup annotations on Linux
-      if: runner.os == 'Linux'
-      run: python -m pip install pytest-github-actions-annotate-failures
-
-    # First build - C++11 mode and inplace
-    - name: Configure C++11 ${{ matrix.args }}
-      run: >
-        cmake -S . -B .
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=11
-        ${{ matrix.args }}
-
-    - name: Build C++11
-      run: cmake --build . -j 2
-
-    - name: Python tests C++11
-      run: cmake --build . --target pytest -j 2
-
-    - name: C++11 tests
-      # TODO: Figure out how to load the DLL on Python 3.8+
-      if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
-      run: cmake --build .  --target cpptest -j 2
-
-    - name: Interface test C++11
-      run: cmake --build . --target test_cmake_build
-
-    - name: Clean directory
-      run: git clean -fdx
-
-    # Second build - C++17 mode and in a build directory
-    - name: Configure ${{ matrix.args2 }}
-      run: >
-        cmake -S . -B build2
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=17
-        ${{ matrix.args }}
-        ${{ matrix.args2 }}
-
-    - name: Build
-      run: cmake --build build2 -j 2
-
-    - name: Python tests
-      run: cmake --build build2 --target pytest
-
-    - name: C++ tests
-      # TODO: Figure out how to load the DLL on Python 3.8+
-      if: "!(runner.os == 'Windows' && (matrix.python == 3.8 || matrix.python == 3.9 || matrix.python == '3.10-dev'))"
-      run: cmake --build build2 --target cpptest
-
-    - name: Interface test
-      run: cmake --build build2 --target test_cmake_build
-
-    # Eventually Microsoft might have an action for setting up
-    # MSVC, but for now, this action works:
-    - name: Prepare compiler environment for Windows 🐍 2.7
-      if: matrix.python == 2.7 && runner.os == 'Windows'
-      uses: ilammy/msvc-dev-cmd@v1.9.0
-      with:
-        arch: x64
-
-    # This makes two environment variables available in the following step(s)
-    - name: Set Windows 🐍 2.7 environment variables
-      if: matrix.python == 2.7 && runner.os == 'Windows'
-      shell: bash
-      run: |
-        echo "DISTUTILS_USE_SDK=1" >> $GITHUB_ENV
-        echo "MSSdk=1" >> $GITHUB_ENV
-
-    # This makes sure the setup_helpers module can build packages using
-    # setuptools
-    - name: Setuptools helpers test
-      run: pytest tests/extra_setuptools
-
-
-  deadsnakes:
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-        - python-version: 3.9
-          python-debug: true
-          valgrind: true
-        - python-version: 3.10-dev
-          python-debug: false
-
-    name: "🐍 ${{ matrix.python-version }}${{ matrix.python-debug && '-dbg' || '' }} (deadsnakes)${{ matrix.valgrind && ' • Valgrind' || '' }} • x64"
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup Python ${{ matrix.python-version }} (deadsnakes)
-      uses: deadsnakes/action@v2.1.1
-      with:
-        python-version: ${{ matrix.python-version }}
-        debug: ${{ matrix.python-debug }}
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v1.9
-
-    - name: Valgrind cache
-      if: matrix.valgrind
-      uses: actions/cache@v2
-      id: cache-valgrind
-      with:
-        path: valgrind
-        key: 3.16.1 # Valgrind version
-
-    - name: Compile Valgrind
-      if: matrix.valgrind && steps.cache-valgrind.outputs.cache-hit != 'true'
-      run: |
-        VALGRIND_VERSION=3.16.1
-        curl https://sourceware.org/pub/valgrind/valgrind-$VALGRIND_VERSION.tar.bz2 -o - | tar xj
-        mv valgrind-$VALGRIND_VERSION valgrind
-        cd valgrind
-        ./configure
-        make -j 2 > /dev/null
-
-    - name: Install Valgrind
-      if: matrix.valgrind
-      working-directory: valgrind
-      run: |
-        sudo make install
-        sudo apt-get update
-        sudo apt-get install libc6-dbg  # Needed by Valgrind
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
-
-    - name: Configure
-      run: >
-        cmake -S . -B build
-        -DCMAKE_BUILD_TYPE=Debug
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=17
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Run Valgrind on Python tests
-      if: matrix.valgrind
-      run: cmake --build build --target memcheck
-
-
-  # Testing on clang using the excellent silkeh clang docker images
-  clang:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        clang:
-          - 3.6
-          - 3.7
-          - 3.9
-          - 7
-          - 9
-          - dev
-        std:
-          - 11
-        include:
-          - clang: 5
-            std: 14
-          - clang: 10
-            std: 20
-          - clang: 10
-            std: 17
-
-    name: "🐍 3 • Clang ${{ matrix.clang }} • C++${{ matrix.std }} • x64"
-    container: "silkeh/clang:${{ matrix.clang }}"
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Add wget and python3
-      run: apt-get update && apt-get install -y python3-dev python3-numpy python3-pytest libeigen3-dev
-
-    - name: Configure
-      shell: bash
-      run: >
-        cmake -S . -B build
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build
-
-
-  # Testing NVCC; forces sources to behave like .cu files
-  cuda:
-    runs-on: ubuntu-latest
-    name: "🐍 3.8 • CUDA 11 • Ubuntu 20.04"
-    container: nvidia/cuda:11.0-devel-ubuntu20.04
-
-    steps:
-    - uses: actions/checkout@v2
-
-    # tzdata will try to ask for the timezone, so set the DEBIAN_FRONTEND
-    - name: Install 🐍 3
-      run: apt-get update && DEBIAN_FRONTEND="noninteractive" apt-get install -y cmake git python3-dev python3-pytest python3-numpy
-
-    - name: Configure
-      run: cmake -S . -B build -DPYBIND11_CUDA_TESTS=ON -DPYBIND11_WERROR=ON -DDOWNLOAD_CATCH=ON
-
-    - name: Build
-      run: cmake --build build -j2 --verbose
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-
-# TODO: Internal compiler error - report to NVidia
-#  # Testing CentOS 8 + PGI compilers
-#  centos-nvhpc8:
-#    runs-on: ubuntu-latest
-#    name: "🐍 3 • CentOS8 / PGI 20.11 • x64"
-#    container: centos:8
-#
-#    steps:
-#    - uses: actions/checkout@v2
-#
-#    - name: Add Python 3 and a few requirements
-#      run: yum update -y && yum install -y git python3-devel python3-numpy python3-pytest make environment-modules
-#
-#    - name: Install CMake with pip
-#      run: |
-#        python3 -m pip install --upgrade pip
-#        python3 -m pip install cmake --prefer-binary
-#
-#    - name: Install NVidia HPC SDK
-#      run: >
-#        yum -y install
-#        https://developer.download.nvidia.com/hpc-sdk/20.11/nvhpc-20-11-20.11-1.x86_64.rpm
-#        https://developer.download.nvidia.com/hpc-sdk/20.11/nvhpc-2020-20.11-1.x86_64.rpm
-#
-#    - name: Configure
-#      shell: bash
-#      run: |
-#        source /etc/profile.d/modules.sh
-#        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/20.11
-#        cmake -S . -B build -DDOWNLOAD_CATCH=ON -DCMAKE_CXX_STANDARD=14 -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-#
-#    - name: Build
-#      run: cmake --build build -j 2 --verbose
-#
-#    - name: Python tests
-#      run: cmake --build build --target pytest
-#
-#    - name: C++ tests
-#      run: cmake --build build --target cpptest
-#
-#    - name: Interface test
-#      run: cmake --build build --target test_cmake_build
-
-
-  # Testing on CentOS 7 + PGI compilers, which seems to require more workarounds
-  centos-nvhpc7:
-    runs-on: ubuntu-latest
-    name: "🐍 3 • CentOS7 / PGI 20.9 • x64"
-    container: centos:7
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Add Python 3 and a few requirements
-      run: yum update -y && yum install -y epel-release && yum install -y git python3-devel make environment-modules cmake3
-
-    - name: Install NVidia HPC SDK
-      run:  yum -y install https://developer.download.nvidia.com/hpc-sdk/20.9/nvhpc-20-9-20.9-1.x86_64.rpm https://developer.download.nvidia.com/hpc-sdk/20.9/nvhpc-2020-20.9-1.x86_64.rpm
-
-    # On CentOS 7, we have to filter a few tests (compiler internal error)
-    # and allow deeper template recursion (not needed on CentOS 8 with a newer
-    # standard library). On some systems, you many need further workarounds:
-    # https://github.com/pybind/pybind11/pull/2475
-    - name: Configure
-      shell: bash
-      run: |
-        source /etc/profile.d/modules.sh
-        module load /opt/nvidia/hpc_sdk/modulefiles/nvhpc/20.9
-        cmake3 -S . -B build -DDOWNLOAD_CATCH=ON \
-                            -DCMAKE_CXX_STANDARD=11 \
-                            -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)") \
-                            -DCMAKE_CXX_FLAGS="-Wc,--pending_instantiations=0" \
-                            -DPYBIND11_TEST_FILTER="test_smart_ptr.cpp;test_virtual_functions.cpp"
-
-    # Building before installing Pip should produce a warning but not an error
-    - name: Build
-      run: cmake3 --build build -j 2 --verbose
-
-    - name: Install CMake with pip
-      run: |
-        python3 -m pip install --upgrade pip
-        python3 -m pip install pytest
-
-    - name: Python tests
-      run: cmake3 --build build --target pytest
-
-    - name: C++ tests
-      run: cmake3 --build build --target cpptest
-
-    - name: Interface test
-      run: cmake3 --build build --target test_cmake_build
-
-
-  # Testing on GCC using the GCC docker images (only recent images supported)
-  gcc:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        gcc:
-          - 7
-          - latest
-        std:
-          - 11
-        include:
-          - gcc: 10
-            std: 20
-
-    name: "🐍 3 • GCC ${{ matrix.gcc }} • C++${{ matrix.std }}• x64"
-    container: "gcc:${{ matrix.gcc }}"
-
-    steps:
-    - uses: actions/checkout@v1
-
-    - name: Add Python 3
-      run: apt-get update; apt-get install -y python3-dev python3-numpy python3-pytest python3-pip libeigen3-dev
-
-    - name: Update pip
-      run: python3 -m pip install --upgrade pip
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v1.9
-
-    - name: Configure
-      shell: bash
-      run: >
-        cmake -S . -B build
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build
-
-
   # Testing on ICC using the oneAPI apt repo
-  icc:
+  icc11:
     runs-on: ubuntu-20.04
     strategy:
       fail-fast: false
 
-    name: "🐍 3 • ICC latest • x64"
+    name: "🐍 3 • ICC-11 latest • x64"
 
     steps:
     - uses: actions/checkout@v2
@@ -533,6 +74,37 @@ jobs:
         set +e; source /opt/intel/oneapi/setvars.sh; set -e
         cmake --build build-11 --target test_cmake_build
 
+  icc17:
+    runs-on: ubuntu-20.04
+    strategy:
+      fail-fast: false
+
+    name: "🐍 3 • ICC-17 latest • x64"
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Add apt repo
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y wget build-essential pkg-config cmake ca-certificates gnupg
+        wget https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS-2023.PUB
+        sudo apt-key add GPG-PUB-KEY-INTEL-SW-PRODUCTS-2023.PUB
+        echo "deb https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
+
+    - name: Add ICC & Python 3
+      run: sudo apt-get update; sudo apt-get install -y intel-oneapi-compiler-dpcpp-cpp-and-cpp-classic cmake python3-dev python3-numpy python3-pytest python3-pip
+
+    - name: Update pip
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        python3 -m pip install --upgrade pip
+
+    - name: Install dependencies
+      run: |
+        set +e; source /opt/intel/oneapi/setvars.sh; set -e
+        python3 -m pip install -r tests/requirements.txt --prefer-binary
+
     - name: Configure C++17
       run: |
         set +e; source /opt/intel/oneapi/setvars.sh; set -e
@@ -564,298 +136,3 @@ jobs:
       run: |
         set +e; source /opt/intel/oneapi/setvars.sh; set -e
         cmake --build build-17 --target test_cmake_build
-
-
-  # Testing on CentOS (manylinux uses a centos base, and this is an easy way
-  # to get GCC 4.8, which is the manylinux1 compiler).
-  centos:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        centos:
-          - 7  # GCC 4.8
-          - 8
-
-    name: "🐍 3 • CentOS ${{ matrix.centos }} • x64"
-    container: "centos:${{ matrix.centos }}"
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Add Python 3
-      run: yum update -y && yum install -y python3-devel gcc-c++ make git
-
-    - name: Update pip
-      run: python3 -m pip install --upgrade pip
-
-    - name: Install dependencies
-      run: python3 -m pip install cmake -r tests/requirements.txt --prefer-binary
-
-    - name: VAR_BUILD_TYPE 7
-      if: matrix.centos == 7
-      run: echo Release > VAR_BUILD_TYPE
-
-    # Using Debug to avoid segfault that appeared around 2021-06-04,
-    # apparently when the gcc version changed from 8.3 to 8.4.
-    - name: VAR_BUILD_TYPE 8
-      if: matrix.centos == 8
-      run: echo Debug > VAR_BUILD_TYPE
-
-    - name: Configure
-      shell: bash
-      run: >
-        cmake -S . -B build
-        -DCMAKE_BUILD_TYPE=$(cat VAR_BUILD_TYPE)
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=11
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Build
-      run: cmake --build build -j 2
-
-    - name: Python tests
-      run: cmake --build build --target pytest
-
-    - name: C++ tests
-      run: cmake --build build --target cpptest
-
-    - name: Interface test
-      run: cmake --build build --target test_cmake_build
-
-
-  # This tests an "install" with the CMake tools
-  install-classic:
-    name: "🐍 3.5 • Debian • x86 •  Install"
-    runs-on: ubuntu-latest
-    container: i386/debian:stretch
-
-    steps:
-    - uses: actions/checkout@v1
-
-    - name: Install requirements
-      run: |
-        apt-get update
-        apt-get install -y git make cmake g++ libeigen3-dev python3-dev python3-pip
-        pip3 install "pytest==3.1.*"
-
-    - name: Configure for install
-      run: >
-        cmake .
-        -DPYBIND11_INSTALL=1 -DPYBIND11_TEST=0
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-
-    - name: Make and install
-      run: make install
-
-    - name: Copy tests to new directory
-      run: cp -a tests /pybind11-tests
-
-    - name: Make a new test directory
-      run: mkdir /build-tests
-
-    - name: Configure tests
-      run: >
-        cmake ../pybind11-tests
-        -DDOWNLOAD_CATCH=ON
-        -DPYBIND11_WERROR=ON
-        -DPYTHON_EXECUTABLE=$(python3 -c "import sys; print(sys.executable)")
-      working-directory: /build-tests
-
-    - name: Run tests
-      run: make pytest -j 2
-      working-directory: /build-tests
-
-
-  # This verifies that the documentation is not horribly broken, and does a
-  # basic sanity check on the SDist.
-  doxygen:
-    name: "Documentation build test"
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - uses: actions/setup-python@v2
-
-    - name: Install Doxygen
-      run: sudo apt-get install -y doxygen librsvg2-bin # Changed to rsvg-convert in 20.04
-
-    - name: Install docs & setup requirements
-      run: python3 -m pip install -r docs/requirements.txt
-
-    - name: Build docs
-      run: python3 -m sphinx -W -b html docs docs/.build
-
-    - name: Make SDist
-      run: python3 setup.py sdist
-
-    - run: git status --ignored
-
-    - name: Check local include dir
-      run: >
-        ls pybind11;
-        python3 -c "import pybind11, pathlib; assert (a := pybind11.get_include()) == (b := str(pathlib.Path('include').resolve())), f'{a} != {b}'"
-
-    - name: Compare Dists (headers only)
-      working-directory: include
-      run: |
-        python3 -m pip install --user -U ../dist/*
-        installed=$(python3 -c "import pybind11; print(pybind11.get_include() + '/pybind11')")
-        diff -rq $installed ./pybind11
-
-  win32:
-    strategy:
-      fail-fast: false
-      matrix:
-        python:
-        - 3.5
-        - 3.6
-        - 3.7
-        - 3.8
-        - 3.9
-        - pypy3
-        # TODO: fix hang on pypy2
-
-        include:
-          - python: 3.9
-            args: -DCMAKE_CXX_STANDARD=20 -DDOWNLOAD_EIGEN=OFF
-          - python: 3.8
-            args: -DCMAKE_CXX_STANDARD=17
-
-    name: "🐍 ${{ matrix.python }} • MSVC 2019 • x86 ${{ matrix.args }}"
-    runs-on: windows-latest
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup Python ${{ matrix.python }}
-      uses: actions/setup-python@v2
-      with:
-        python-version: ${{ matrix.python }}
-        architecture: x86
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v1.9
-
-    - name: Prepare MSVC
-      uses: ilammy/msvc-dev-cmd@v1.9.0
-      with:
-        arch: x86
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
-
-    # First build - C++11 mode and inplace
-    - name: Configure ${{ matrix.args }}
-      run: >
-        cmake -S . -B build
-        -G "Visual Studio 16 2019" -A Win32
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        ${{ matrix.args }}
-    - name: Build C++11
-      run: cmake --build build -j 2
-
-    - name: Run tests
-      run: cmake --build build -t pytest
-
-  win32-msvc2015:
-    name: "🐍 ${{ matrix.python }} • MSVC 2015 • x64"
-    runs-on: windows-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        python:
-          - 2.7
-          - 3.6
-          - 3.7
-          # todo: check/cpptest does not support 3.8+ yet
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup 🐍 ${{ matrix.python }}
-      uses: actions/setup-python@v2
-      with:
-        python-version: ${{ matrix.python }}
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v1.9
-
-    - name: Prepare MSVC
-      uses: ilammy/msvc-dev-cmd@v1.9.0
-      with:
-        toolset: 14.0
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
-
-    # First build - C++11 mode and inplace
-    - name: Configure
-      run: >
-        cmake -S . -B build
-        -G "Visual Studio 14 2015" -A x64
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-
-    - name: Build C++14
-      run: cmake --build build -j 2
-
-    - name: Run all checks
-      run: cmake --build build -t check
-
-
-  win32-msvc2017:
-    name: "🐍 ${{ matrix.python }} • MSVC 2017 • x64"
-    runs-on: windows-2016
-    strategy:
-      fail-fast: false
-      matrix:
-        python:
-          - 2.7
-          - 3.5
-          - 3.7
-        std:
-          - 14
-
-        include:
-          - python: 2.7
-            std: 17
-            args: >
-              -DCMAKE_CXX_FLAGS="/permissive- /EHsc /GR"
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup 🐍 ${{ matrix.python }}
-      uses: actions/setup-python@v2
-      with:
-        python-version: ${{ matrix.python }}
-
-    - name: Update CMake
-      uses: jwlawson/actions-setup-cmake@v1.9
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
-
-    # First build - C++11 mode and inplace
-    - name: Configure
-      run: >
-        cmake -S . -B build
-        -G "Visual Studio 15 2017" -A x64
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DDOWNLOAD_EIGEN=ON
-        -DCMAKE_CXX_STANDARD=${{ matrix.std }}
-        ${{ matrix.args }}
-
-    - name: Build ${{ matrix.std }}
-      run: cmake --build build -j 2
-
-    - name: Run all checks
-      run: cmake --build build -t check
diff --git a/.github/workflows/configure.yml b/.github/workflows/configure.yml
deleted file mode 100644
index abcff1dde5..0000000000
--- a/.github/workflows/configure.yml
+++ /dev/null
@@ -1,84 +0,0 @@
-name: Config
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-      - master
-      - stable
-      - v*
-
-jobs:
-  # This tests various versions of CMake in various combinations, to make sure
-  # the configure step passes.
-  cmake:
-    strategy:
-      fail-fast: false
-      matrix:
-        runs-on: [ubuntu-latest, macos-latest, windows-latest]
-        arch: [x64]
-        cmake: [3.18]
-
-        include:
-        - runs-on: ubuntu-latest
-          arch: x64
-          cmake: 3.4
-
-        - runs-on: macos-latest
-          arch: x64
-          cmake: 3.7
-
-        - runs-on: windows-2016
-          arch: x86
-          cmake: 3.8
-
-        - runs-on: windows-2016
-          arch: x86
-          cmake: 3.18
-
-    name: 🐍 3.7 • CMake ${{ matrix.cmake }} • ${{ matrix.runs-on }}
-    runs-on: ${{ matrix.runs-on }}
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup Python 3.7
-      uses: actions/setup-python@v2
-      with:
-        python-version: 3.7
-        architecture: ${{ matrix.arch }}
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt
-
-    # An action for adding a specific version of CMake:
-    #   https://github.com/jwlawson/actions-setup-cmake
-    - name: Setup CMake ${{ matrix.cmake }}
-      uses: jwlawson/actions-setup-cmake@v1.9
-      with:
-        cmake-version: ${{ matrix.cmake }}
-
-    # These steps use a directory with a space in it intentionally
-    - name: Make build directories
-      run: mkdir "build dir"
-
-    - name: Configure
-      working-directory: build dir
-      shell: bash
-      run: >
-        cmake ..
-        -DPYBIND11_WERROR=ON
-        -DDOWNLOAD_CATCH=ON
-        -DPYTHON_EXECUTABLE=$(python -c "import sys; print(sys.executable)")
-
-    # Only build and test if this was manually triggered in the GitHub UI
-    - name: Build
-      working-directory: build dir
-      if: github.event_name == 'workflow_dispatch'
-      run: cmake --build . --config Release
-
-    - name: Test
-      working-directory: build dir
-      if: github.event_name == 'workflow_dispatch'
-      run: cmake --build . --config Release --target check
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
deleted file mode 100644
index ab7b40503a..0000000000
--- a/.github/workflows/format.yml
+++ /dev/null
@@ -1,48 +0,0 @@
-# This is a format job. Pre-commit has a first-party GitHub action, so we use
-# that: https://github.com/pre-commit/action
-
-name: Format
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-    - master
-    - stable
-    - "v*"
-
-jobs:
-  pre-commit:
-    name: Format
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v2
-    - uses: actions/setup-python@v2
-    - uses: pre-commit/action@v2.0.3
-      with:
-        # Slow hooks are marked with manual - slow is okay here, run them too
-        extra_args: --hook-stage manual --all-files
-
-  clang-tidy:
-    # When making changes here, please also review the "Clang-Tidy" section
-    # in .github/CONTRIBUTING.md and update as needed.
-    name: Clang-Tidy
-    runs-on: ubuntu-latest
-    container: silkeh/clang:12
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Install requirements
-      run: apt-get update && apt-get install -y python3-dev python3-pytest
-
-    - name: Configure
-      run: >
-        cmake -S . -B build
-        -DCMAKE_CXX_CLANG_TIDY="$(which clang-tidy)"
-        -DDOWNLOAD_EIGEN=ON
-        -DDOWNLOAD_CATCH=ON
-        -DCMAKE_CXX_STANDARD=17
-
-    - name: Build
-      run: cmake --build build -j 2 -- --keep-going
diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
deleted file mode 100644
index d2b5979681..0000000000
--- a/.github/workflows/labeler.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-name: Labeler
-on:
-  pull_request_target:
-    types: [closed]
-
-jobs:
-  label:
-    name: Labeler
-    runs-on: ubuntu-latest
-    steps:
-
-    - uses: actions/labeler@main
-      if: github.event.pull_request.merged == true
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        configuration-path: .github/labeler_merged.yml
diff --git a/.github/workflows/pip.yml b/.github/workflows/pip.yml
deleted file mode 100644
index 5547a5e285..0000000000
--- a/.github/workflows/pip.yml
+++ /dev/null
@@ -1,103 +0,0 @@
-name: Pip
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-    - master
-    - stable
-    - v*
-  release:
-    types:
-    - published
-
-jobs:
-  # This builds the sdists and wheels and makes sure the files are exactly as
-  # expected. Using Windows and Python 2.7, since that is often the most
-  # challenging matrix element.
-  test-packaging:
-    name: 🐍 2.7 • 📦 tests • windows-latest
-    runs-on: windows-latest
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup 🐍 2.7
-      uses: actions/setup-python@v2
-      with:
-        python-version: 2.7
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt --prefer-binary
-
-    - name: Python Packaging tests
-      run: pytest tests/extra_python_package/
-
-
-  # This runs the packaging tests and also builds and saves the packages as
-  # artifacts.
-  packaging:
-    name: 🐍 3.8 • 📦 & 📦 tests • ubuntu-latest
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Setup 🐍 3.8
-      uses: actions/setup-python@v2
-      with:
-        python-version: 3.8
-
-    - name: Prepare env
-      run: python -m pip install -r tests/requirements.txt build twine --prefer-binary
-
-    - name: Python Packaging tests
-      run: pytest tests/extra_python_package/
-
-    - name: Build SDist and wheels
-      run: |
-        python -m build
-        PYBIND11_GLOBAL_SDIST=1 python -m build
-
-    - name: Check metadata
-      run: twine check dist/*
-
-    - name: Save standard package
-      uses: actions/upload-artifact@v2
-      with:
-        name: standard
-        path: dist/pybind11-*
-
-    - name: Save global package
-      uses: actions/upload-artifact@v2
-      with:
-        name: global
-        path: dist/pybind11_global-*
-
-
-
-  # When a GitHub release is made, upload the artifacts to PyPI
-  upload:
-    name: Upload to PyPI
-    runs-on: ubuntu-latest
-    if: github.event_name == 'release' && github.event.action == 'published'
-    needs: [packaging]
-
-    steps:
-    - uses: actions/setup-python@v2
-
-    # Downloads all to directories matching the artifact names
-    - uses: actions/download-artifact@v2
-
-    - name: Publish standard package
-      uses: pypa/gh-action-pypi-publish@v1.4.2
-      with:
-        password: ${{ secrets.pypi_password }}
-        packages_dir: standard/
-
-    - name: Publish global package
-      uses: pypa/gh-action-pypi-publish@v1.4.2
-      with:
-        password: ${{ secrets.pypi_password_global }}
-        packages_dir: global/
diff --git a/include/pybind11/pybind11.h b/include/pybind11/pybind11.h
index b4aab51a7c..af8e730d3f 100644
--- a/include/pybind11/pybind11.h
+++ b/include/pybind11/pybind11.h
@@ -12,29 +12,19 @@
 
 #if defined(__INTEL_COMPILER)
 #  pragma warning push
-#  pragma warning disable 68    // integer conversion resulted in a change of sign
-#  pragma warning disable 186   // pointless comparison of unsigned integer with zero
 #  pragma warning disable 878   // incompatible exception specifications
-#  pragma warning disable 1334  // the "template" keyword used for syntactic disambiguation may only be used within a template
-#  pragma warning disable 1682  // implicit conversion of a 64-bit integral type to a smaller integral type (potential portability problem)
-#  pragma warning disable 1786  // function "strdup" was declared deprecated
-#  pragma warning disable 1875  // offsetof applied to non-POD (Plain Old Data) types is nonstandard
 #  pragma warning disable 2196  // warning #2196: routine is both "inline" and "noinline"
 #elif defined(_MSC_VER)
 #  pragma warning(push)
 #  pragma warning(disable: 4100) // warning C4100: Unreferenced formal parameter
 #  pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
-#  pragma warning(disable: 4512) // warning C4512: Assignment operator was implicitly defined as deleted
 #  pragma warning(disable: 4800) // warning C4800: 'int': forcing value to bool 'true' or 'false' (performance warning)
 #  pragma warning(disable: 4996) // warning C4996: The POSIX name for this item is deprecated. Instead, use the ISO C and C++ conformant name
-#  pragma warning(disable: 4702) // warning C4702: unreachable code
 #  pragma warning(disable: 4522) // warning C4522: multiple assignment operators specified
 #  pragma warning(disable: 4505) // warning C4505: 'PySlice_GetIndicesEx': unreferenced local function has been removed (PyPy only)
 #elif defined(__GNUG__) && !defined(__clang__)
 #  pragma GCC diagnostic push
 #  pragma GCC diagnostic ignored "-Wunused-but-set-parameter"
-#  pragma GCC diagnostic ignored "-Wunused-but-set-variable"
-#  pragma GCC diagnostic ignored "-Wmissing-field-initializers"
 #  pragma GCC diagnostic ignored "-Wattributes"
 #  if __GNUC__ >= 7
 #    pragma GCC diagnostic ignored "-Wnoexcept-type"
diff --git a/tools/repeat_command.py b/tools/repeat_command.py
new file mode 100644
index 0000000000..3934d5d6f5
--- /dev/null
+++ b/tools/repeat_command.py
@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import collections
+import subprocess
+import sys
+
+
+def run(args):
+    num_repeats = int(args[0])
+    cmd_and_args = args[1:]
+    assert cmd_and_args
+    if num_repeats < 0:
+        # Shortcut to turn this script into a completely transparent no-op.
+        return subprocess.call(cmd_and_args)
+    if not num_repeats:
+        # Can be used as a simple trick to skip the command entirely.
+        print("REPEAT_COMMAND:SKIP", cmd_and_args)
+        print()
+        sys.stdout.flush()
+        return
+    print("REPEAT_COMMAND:CMD_AND_ARGS", cmd_and_args)
+    print()
+    retcode_counts = collections.defaultdict(int)
+    first_non_zero_retcode = 0
+    for ix in range(num_repeats):
+        print("REPEAT_COMMAND:CALL", ix + 1)
+        sys.stdout.flush()
+        retcode = subprocess.call(cmd_and_args)
+        print("REPEAT_COMMAND:RETCODE", retcode)
+        print()
+        retcode_counts[retcode] += 1
+        if retcode and not first_non_zero_retcode:
+            first_non_zero_retcode = retcode
+    print("REPEAT_COMMAND:RETCODE_COUNTS", list(sorted(retcode_counts.items())))
+    print("REPEAT_COMMAND:FIRST_NON_ZERO_RETCODE", first_non_zero_retcode)
+    print()
+    sys.stdout.flush()
+    return first_non_zero_retcode
+
+
+if __name__ == "__main__":
+    sys.exit(run(args=sys.argv[1:]))