Library Patches

Two third-party libraries are modified in the tree itself. book/lib/paged.browser.js is a patched copy of paged.js v0.4.3 (MIT); the thirteen fast-*.mjs files there are side-effecting shims applied to pdf-lib’s live exports before each PDF process phase. This section documents every change to those two: what the upstream behaviour was, why it was unsuitable for the build pipeline, and what was changed.

A third library is modified, but nowhere on disk. The accessibility scan rewrites the axe-core bundle as it injects it — SOURCE_PATCHES in scripts/lib/axe-scan.mjs replaces Color2’s six WeakMap-emulated #private fields with plain own properties, worth about a quarter of the scan’s running time. Nothing under node_modules/ is touched, so the substitution has to be re-proved against each axe-core upgrade rather than surviving one. Two gates do that, and both are needed: check_axe_patch_equiv.mjs compares the colour values the patched and stock bundles produce, and check_a11y_fingerprint.mjs compares the findings across the whole scan matrix.

Sub-pages

• Paged.js Patches — changes to book/lib/paged.browser.js: the synchronous execution chain, hook dispatch fast-paths, DOM lookup optimizations, layout correctness fixes, and miscellaneous headless-specific changes.
• pdf-lib Patches — the thirteen fast-*.mjs shims and parallel-deflate.mjs that retune pdf-lib’s parser, object model, and serializer for the process phase.