What bootstrap V81 demonstrates

The V81 dossier records four final reconstructions: B2 and C2 on Windows, and B2 and C2 on Linux/WSL. Each rebuilds 74 units in a new directory using project objects --no-incremental, without LTO or retained project objects.

The generations also rebuild their providers: 36 on Windows and 35 on Linux. Compiler B2 and C2 are byte-identical within each host. Their recorded digests are:

Windows x86-64
4ff2300d30fbe99a4c541481e0fab9df284d77c32d1df082084440b9718854c9

Linux x86-64
e3d6fc744f0768d19a3f44ca93eddcb90cc3f89caee536f68f8f5ce486eae1e7

Identity is established within each operating system. A Windows PE and a Linux ELF are not claimed to have identical bytes. Manifests associate each digest with its artifact.

Stage0 remains an AST oracle for that validation corpus, rather than the constructor of B and C. Global Stage3 promotion is explicitly open, and the installed toolchain is retained.

The dossier reports 147 complete programs and 1472 checks per run, 38 runtime contracts per generation and host, and layout checks across ten profiles. These are retained V81 results. Publication smoke tests are recorded separately and do not replace full reconstruction.

Support expands through evidence for missing routes: inputs, emitted artifacts, dependencies and execution. Compatibility claims must match the scope of those checks.