I. Engineering Highlights (What Sets This Apart)

1. Layered decision engine: on the page, RecoveryCoordinator unifies recovery decisions across Webpack, Vite, DOM Observer, and SystemJS, while ownership / in-flight registries decide who may take over one logicalKey. Service Worker keeps a separate legacy Resolver for fetch-layer subresources. This preserves shared page-side semantics without forcing SW constraints into every adapter.

2. Full coverage of your own build outputs: Not just entry <script>/<link>, but also Webpack chunk loader (__webpack_require__.l + non-JS CSS chunk loaders in __webpack_require__.f), Vite dynamic import() in output (current implementation: post-emit writeBundle + es-module-lexer + MagicString + __RF__.load), vite:preloadError and async CSS/JS ordering, mini-css-extract style chunks, and other builder-coupled paths — a different boundary from "swap third-party library CDN" plugins.

3. Aligned with browser quirks: Failed URL cache for type="module" / dynamic import(), <script> cannot be fixed with cloneNode, getAttribute('src') vs .src for rule prefix / vs absolute URL — all handled explicitly at runtime (__rf= cache bust, strip timing), reducing trial-and-error for integrators.

4. Ownership boundaries to reduce duplicate work and races: e.g. Webpack data-webpack <script> → adapter, Observer skips; same-attribute <link> → Observer. Page-side ownership admission happens first, then RecoveryCoordinator lets concurrent work from the same owner share one in-flight recovery Promise — avoiding double-processing of async JS and white-screen chains.

5. Observability and ops switches: CustomEvents (rf:retry / rf:fallback / rf:success / rf:error) are granular enough for monitoring. To tell whether page-side fallback really started, prefer rf:retry / rf:fallback over parsing legacy Resolver-style reason strings from rf:error. Kill switch and cross-tab circuit (localStorage) complement "change paths only via release" approaches.

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