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      "adoption": "contract",
      "summary": "Writes hot functions and call trees as terminal-readable Markdown.",
      "boundary": "Generated profiling evidence stays local and is not served by the gallery.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#cpu-prof-md",
      "assetIds": [
        "bun-1.4-cpu-prof-devtools"
      ],
      "contractFiles": [
        "tests/bun-1.4.0-observability-contract.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "heap-profile-markdown",
      "domain": "observability",
      "symbol": "--heap-prof-md",
      "changeKind": "release-window",
      "adoption": "contract",
      "summary": "Writes retained types, objects and retaining chains as Markdown.",
      "boundary": "Profiles can contain sensitive runtime data and remain local artifacts.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#heap-prof-md",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-1.4.0-observability-contract.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "bundle-metafile-markdown",
      "domain": "bundler",
      "symbol": "bun build --metafile-md",
      "changeKind": "release-window",
      "adoption": "integrated",
      "summary": "Writes bundle size, entry-point and import-chain analysis as Markdown.",
      "boundary": "Build evidence only; the JSON asset manifest remains the media source of truth.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#bun-build-metafile-md",
      "docsUrl": "https://bun.com/docs/bundler",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-1.4-cli-example.test.ts"
      ],
      "chapterId": "bun-build"
    },
    {
      "id": "node-sqlite-compatibility",
      "domain": "runtime",
      "symbol": "node:sqlite",
      "changeKind": "compatibility",
      "adoption": "contract",
      "summary": "Bun reports full coverage of the referenced Node sqlite test module in 1.4.",
      "boundary": "Compatibility claim is upstream; project behavior is separately contract-tested.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#node-sqlite",
      "assetIds": [
        "bun-1.4-node-sqlite"
      ],
      "contractFiles": [
        "tests/bun-1.4.0-bugfix-contract.test.ts"
      ]
    },
    {
      "id": "node-test-compatibility",
      "domain": "runtime",
      "symbol": "Node.js compatibility",
      "changeKind": "compatibility",
      "adoption": "upstream-claim",
      "summary": "Bun reports 1,517 additional passing Node.js tests in the 1.4 release.",
      "boundary": "Upstream suite counts are displayed as claims and are not re-benchmarked here.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#node-js-compatibility",
      "assetIds": [
        "bun-1.4-node-test-suite-progress"
      ],
      "contractFiles": []
    },
    {
      "id": "react-compiler-built-in",
      "domain": "bundler",
      "symbol": "React Compiler",
      "changeKind": "new",
      "adoption": "candidate",
      "summary": "Enables the React Compiler in Bun build flows without a separate Babel setup.",
      "boundary": "Candidate for React build surfaces; not required by this static portal.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#built-in-react-compiler",
      "assetIds": [
        "bun-1.4-react-compiler"
      ],
      "contractFiles": [],
      "chapterId": "bun-build"
    },
    {
      "id": "cpu-profile-env-claim",
      "domain": "observability",
      "symbol": "BUN_CPU_PROFILE",
      "changeKind": "release-window",
      "adoption": "upstream-claim",
      "summary": "Bun documents BUN_CPU_PROFILE=1 for processes that cannot receive profiler flags.",
      "boundary": "Not adopted on the pinned runtime; repository subprocesses use explicit flags or BUN_OPTIONS until an executable proof exists.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#dev-tooling",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "markdown-linear-time-claim",
      "domain": "runtime",
      "symbol": "Bun.markdown parser complexity",
      "changeKind": "performance",
      "adoption": "upstream-claim",
      "summary": "Bun reports linear-time Markdown parsing on adversarial input.",
      "boundary": "Upstream complexity claim only; repository tests cover output and security boundaries, not a timing benchmark.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#bun-markdown",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "ffi-performance-claim",
      "domain": "runtime",
      "symbol": "bun:ffi",
      "changeKind": "performance",
      "adoption": "upstream-claim",
      "summary": "Bun reports up to a threefold FFI call-speed improvement.",
      "boundary": "Release benchmark claim only; no gallery code uses FFI.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#3x-faster-bun-ffi",
      "assetIds": [
        "bun-1.4-ffi-3x"
      ],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "source-map-decoding-claim",
      "domain": "runtime",
      "symbol": "source-map decoding",
      "changeKind": "performance",
      "adoption": "upstream-claim",
      "summary": "Bun reports source-map decoding is 3.1 times faster in its release benchmark.",
      "boundary": "Release benchmark claim only; portal source maps follow deployment policy.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#source-map-decoding-is-3-1-faster",
      "assetIds": [
        "bun-1.4-sourcemap-decoding"
      ],
      "contractFiles": [],
      "chapterId": "faster"
    },
    {
      "id": "windows-short-timers",
      "domain": "platform",
      "symbol": "setTimeout / setInterval",
      "changeKind": "fixed",
      "adoption": "upstream-claim",
      "summary": "Windows timers below 15 milliseconds no longer inherit the old coarse scheduling floor.",
      "boundary": "Windows-specific release behavior; this host does not claim a local probe.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#sub-15-ms-timers-on-windows",
      "assetIds": [
        "bun-1.4-windows-timers"
      ],
      "contractFiles": []
    },
    {
      "id": "production-efficiency-claims",
      "domain": "platform",
      "symbol": "Bun runtime",
      "changeKind": "performance",
      "adoption": "upstream-claim",
      "summary": "Bun reports lower server memory, idle CPU and startup costs for the 1.4 runtime.",
      "boundary": "Upstream workload measurements; repository gates do not present them as local benchmarks.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#production",
      "assetIds": [
        "bun-1.4-cpu-usage-cc",
        "bun-1.4-idle-cpu",
        "bun-1.4-nextjs-ssr-fetch-leak"
      ],
      "contractFiles": []
    },
    {
      "id": "bun-1-4-overview",
      "domain": "platform",
      "symbol": "Bun 1.4",
      "changeKind": "compatibility",
      "adoption": "upstream-claim",
      "summary": "Release-level context linking official overview media to the capability graph.",
      "boundary": "Navigation relation only; detailed claims live on their specific records.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4",
      "assetIds": [
        "bun-1.4-og-image",
        "bun-1.4-youtube-overview"
      ],
      "contractFiles": []
    },
    {
      "id": "native-async-stack-traces",
      "domain": "observability",
      "symbol": "async native I/O stack traces",
      "changeKind": "release-window",
      "adoption": "contract",
      "summary": "Native I/O failures retain the JavaScript await site in their async stack trace.",
      "boundary": "Diagnostic behavior only; stack contents can contain local paths and remain private.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#dev-tooling",
      "assetIds": [],
      "contractFiles": [
        "tests/regression/bun-1.3.12.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-no-env-file",
      "domain": "platform",
      "symbol": "--no-env-file / bunfig env = false",
      "changeKind": "release-window",
      "adoption": "contract",
      "summary": "Disables automatic dotenv loading while preserving explicit --env-file inputs.",
      "boundary": "Runtime configuration only; secrets remain externally managed and value-free in proof.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#dev-tooling",
      "docsUrl": "https://bun.com/docs/runtime/environment-variables",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-env-loading.test.ts",
        "tests/bun-runtime-global-flags.test.ts",
        "tests/portal-cli-bun-flags.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-serve-http3-experimental",
      "domain": "server",
      "symbol": "Bun.serve({ http3: true })",
      "changeKind": "release-window",
      "adoption": "candidate",
      "summary": "Adds an experimental HTTP/3 listener beside TLS HTTP/1.1 on the same port.",
      "boundary": "Not enabled in production, Pages Functions, serve-public, or gallery verification.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#http-3-in-bun-serve-experimental",
      "docsUrl": "https://bun.com/docs/runtime/http/server",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "fetch-http2-http3-experimental",
      "domain": "network",
      "symbol": "fetch({ protocol: \"http2\" | \"http3\" })",
      "changeKind": "release-window",
      "adoption": "candidate",
      "summary": "Selects experimental HTTP/2 or HTTP/3 transports for fetch requests.",
      "boundary": "The asset pipeline stays on default HTTPS behavior; no experimental protocol flags.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#http-2-http-3-in-fetch-experimental",
      "docsUrl": "https://bun.com/docs/runtime/networking/fetch",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-serve-production-sourcemaps",
      "domain": "server",
      "symbol": "Bun.serve HTML route sourcemaps",
      "changeKind": "changed",
      "adoption": "candidate",
      "summary": "Production HTML routes no longer serve source maps unless explicitly configured.",
      "boundary": "Cloudflare deployment owns public sourcemap policy; this is not a Pages setting.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#html-routes-sourcemaps-disabled-in-production",
      "docsUrl": "https://bun.com/docs/runtime/http/server",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "fetch-proxy-headers",
      "domain": "network",
      "symbol": "fetch({ proxy: { url, headers } })",
      "changeKind": "release-window",
      "adoption": "candidate",
      "summary": "Allows proxy-specific headers for HTTP and HTTPS destinations.",
      "boundary": "Credentials must come from the vault and must never enter manifests or feed output.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#fetch-proxy-headers",
      "docsUrl": "https://bun.com/docs/runtime/networking/fetch",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "fetch-tls-session-resumption",
      "domain": "network",
      "symbol": "fetch TLS session cache",
      "changeKind": "performance",
      "adoption": "upstream-claim",
      "summary": "Bun reports a per-origin BoringSSL session cache for one-RTT cold reconnections.",
      "boundary": "Transport optimization is upstream-owned and is not treated as a local benchmark.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#tls-session-resumption",
      "docsUrl": "https://bun.com/docs/runtime/networking/fetch",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "fetch-connection-reuse",
      "domain": "network",
      "symbol": "fetch connection pooling",
      "changeKind": "performance",
      "adoption": "upstream-claim",
      "summary": "Bun reports connection reuse through HTTPS proxies and custom TLS configurations.",
      "boundary": "Pooling is runtime-owned; request correctness never depends on a reused connection.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#connection-reuse",
      "docsUrl": "https://bun.com/docs/runtime/networking/fetch",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-json5-native",
      "domain": "runtime",
      "symbol": "Bun.JSON5",
      "changeKind": "release-window",
      "adoption": "contract",
      "summary": "Provides built-in JSON5 parsing, serialization, and module loading.",
      "boundary": "Use only where JSON5 is the declared wire format; do not loosen JSON contracts.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/reference/bun/JSON5",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-1.4.0-bugfix-contract.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-jsonl-native",
      "domain": "runtime",
      "symbol": "Bun.JSONL.parse / parseChunk",
      "changeKind": "release-window",
      "adoption": "candidate",
      "summary": "Parses complete or incrementally streamed newline-delimited JSON.",
      "boundary": "Existing append-only JSONL owners keep their current validation until migrated.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/reference/bun/JSONL",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-jsonc-native",
      "domain": "runtime",
      "symbol": "Bun.JSONC.parse",
      "changeKind": "release-window",
      "adoption": "contract",
      "summary": "Parses JSON with comments and trailing commas using Bun’s built-in parser.",
      "boundary": "Configuration boundary only; emitted registries remain strict JSON.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/reference/bun/JSONC",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-1.4.0-behavior-contract.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-toml-native",
      "domain": "runtime",
      "symbol": "Bun.TOML.parse / stringify",
      "changeKind": "release-window",
      "adoption": "integrated",
      "summary": "Parses TOML 1.1 and exposes serialization in the stable Bun 1.4 contract.",
      "boundary": "TOML is configuration input; validated domain shapes remain separate.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/docs/runtime/toml",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-toml-version-contract.test.ts",
        "tests/config-toml-snapshot.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-archive-native",
      "domain": "runtime",
      "symbol": "Bun.Archive",
      "changeKind": "release-window",
      "adoption": "integrated",
      "summary": "Creates and extracts tar archives, including gzip-compressed release snapshots.",
      "boundary": "Archives preserve reviewed release state; they never authorize media republication.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/reference/bun/Archive",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-1.4-channel-release.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-ansi-layout-native",
      "domain": "runtime",
      "symbol": "Bun.sliceAnsi / wrapAnsi",
      "changeKind": "release-window",
      "adoption": "integrated",
      "summary": "Provides ANSI- and grapheme-aware terminal slicing and wrapping.",
      "boundary": "Terminal presentation only; browser layout remains CSS-owned.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/docs/runtime/utils",
      "assetIds": [],
      "contractFiles": [
        "tests/console-depth.test.ts",
        "tests/regression/bun-1.3.11.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "urlpattern-native",
      "domain": "runtime",
      "symbol": "URLPattern",
      "changeKind": "release-window",
      "adoption": "integrated",
      "summary": "Provides component-aware URL matching and parameter extraction without a package.",
      "boundary": "Route classification uses precompiled patterns and validates decoded values separately.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "assetIds": [],
      "contractFiles": [
        "tests/bun-urlpattern.test.ts",
        "tests/portal-url-planes.test.ts"
      ],
      "chapterId": "what-s-new"
    },
    {
      "id": "compression-streams-native",
      "domain": "runtime",
      "symbol": "CompressionStream / DecompressionStream",
      "changeKind": "release-window",
      "adoption": "candidate",
      "summary": "Exposes Web-standard streaming compression for gzip, deflate, Brotli, and zstd.",
      "boundary": "Remote media fetches still request identity encoding and reject encoded responses.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "response-text-stream",
      "domain": "runtime",
      "symbol": "Response.textStream()",
      "changeKind": "release-window",
      "adoption": "candidate",
      "summary": "Streams a response body as decoded UTF-8 strings.",
      "boundary": "Binary media validation continues to consume bounded bytes, not decoded text.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "post-quantum-webcrypto",
      "domain": "runtime",
      "symbol": "ML-DSA / ML-KEM",
      "changeKind": "new",
      "adoption": "candidate",
      "summary": "Adds NIST post-quantum signatures and key encapsulation to WebCrypto and node:crypto.",
      "boundary": "No protocol or stored-key migration is implied by runtime availability.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-repl-native",
      "domain": "platform",
      "symbol": "bun repl",
      "changeKind": "release-window",
      "adoption": "candidate",
      "summary": "Provides a native interactive REPL with history, completion, highlighting, -e and -p.",
      "boundary": "Interactive operator surface only; automation continues to use deterministic scripts.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/docs/runtime/repl",
      "assetIds": [],
      "contractFiles": [],
      "chapterId": "what-s-new"
    },
    {
      "id": "bun-markdown-cli",
      "domain": "platform",
      "symbol": "bun ./README.md",
      "changeKind": "release-window",
      "adoption": "contract",
      "summary": "Renders a Markdown file directly in the terminal without starting a JavaScript VM.",
      "boundary": "Local presentation only; generated public HTML keeps its separate safety policy.",
      "releaseUrl": "https://bun.com/blog/bun-v1.4#also-built-in",
      "docsUrl": "https://bun.com/docs/runtime/markdown",
      "assetIds": [],
      "contractFiles": [
        "tests/regression/bun-1.3.12.test.ts"
      ],
      "chapterId": "what-s-new"
    }
  ]
}