Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-python@v5, nelonoel/branch-name@v1.0.1. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

flavor=system source=package-manager prefix=/home/runner/work/clad/clad/install

flavor=system: llvm-12 on jammy

libclang-rt-12-dev not in apt-llvm.org for jammy; harmless for LLVM <= 21 (no bundled OOP runtime)