- scr_qs.c ports Node v24's legacy codec quirk-faithfully (the scan state machine with maxKeys' pair budget, unescapeBuffer's code-unit byte truncation with U+FFFD replacement decode, encodeStringified's value rules over the DOM crossing); link-gated by moduleUsesQs, and escape rides the always-linked component encoder
- parse's result is the call site's ParsedUrlQuery dictionary (the networkInterfaces verification stance; the runtime fills the overflow map and groups repeats into string[] buckets), sep/eq/maxKeys complete to Node's defaults, and custom encoder/decoder options fence by name
- decode/encode lower as Node's own aliases; both backends emit the same runtime calls byte-identically
- querystring joins SUPPORTED_BUILTIN_MODULES, the fallback declarations, and the regenerated surface manifest, so npm-static packages requiring it unguarded stop falling back to the island (the shim stays for island code)
- corpus 2460-2464 pin the grammar corners against Node: malformed escapes, '+' vs %2B, repeated keys, maxKeys with empty segments, multi-char/multi-byte separators, astral truncation, and every CJS acquisition spelling
