# Regression fixtures `phrase_quad.pl` is an unmodified snapshot of Ulrich Neumerkel's ISO Prolog `phrase/2-3` quad corpus: Retrieved on 2026-08-11. It is vendored so the regression suite exercises all 58 quads without depending on network access or availability of the source server. `variable_names_quad.pl` is an unmodified snapshot of the 75 machine-readable quads for the ISO read and write option `variable_names/1`: Retrieved on 2026-08-25. It is vendored so all input, output, waiting, and error cases remain release-gated. There used to be a `prologue_quad.pl`/`prologue_quad_runner.pl` pair here: an unmodified snapshot of the Prolog Prologue working draft's machine-readable quads (), plus a runner that loaded `library(prologue)` before including it. It was retired (see git history) once its coverage became strictly redundant with the *live* Prologue source the Neumerkel gate already fetches and checks on every `npm test` run -- the same reason the WG17 syntax matrix has no vendored snapshot of its own either (see [NEUMERKEL-LIVE.md](../conformance/NEUMERKEL-LIVE.md) and [conformance/README.md](../conformance/README.md)). Unlike `phrase_quad.pl` and `variable_names_quad.pl` below, the vendored Prologue corpus also included two open-ended STO/rational-tree generator quads (`member(X,X)`, `select(E,Xs,Xs)`) that made checking it offline disproportionately slow, with no coverage benefit over the live gate to justify the cost.