docs: correct parameter prose in stats/base/dists/gumbel/mgf doc comments

[Planeshifter]

Description

Documentation prose in @stdlib/stats/base/dists/gumbel/mgf referenced the scale parameter as b and labeled the location parameter mu as "mean", and the package's TypeScript declaration opened the declare var JSDoc block with "Gamma distribution" — copy-paste artifacts inconsistent with both mgf's own README/repl.txt and 13/13 sibling packages in the namespace. Six files were normalized to the namespace convention; no behavior, signatures, exports, or test expectations change.

Namespace summary

• Members analyzed: 15 (all non-autogenerated children of stats/base/dists/gumbel/)
• Majority threshold: 12/15 (≥75%)
• Features analyzed: file tree, package.json shape, manifest.json presence, README sections (set + order), test/benchmark/examples filenames, public signature, validation prologue, return kind, error construction, JSDoc shape, doc-comment prose, dependencies
• Features with clear majority that produced advancing corrections: doc-comment prose for the location/scale parameters and the function-summary line (1 outlier package, 13 sites)
• Features with clear majority but no advancing corrections: structural drift on ctor (no native bindings), mgf and skewness (no test/fixtures/julia/) — see Validation
• Features without clear majority: none — every observed feature either reached 75% or had a single dominant value

stats/base/dists/gumbel/mgf

The function-summary line in lib/main.js, lib/factory.js, lib/native.js, docs/types/index.d.ts, include/stdlib/stats/base/dists/gumbel/mgf.h, and src/main.c referenced the scale parameter as `b` (13/13 sibling packages and mgf's own README/repl.txt use `beta`). The @param mu description in lib/main.js, lib/factory.js, and three sites in docs/types/index.d.ts was "mean" rather than "location parameter" (13/13 siblings use "location parameter"; mu is not the mean of the Gumbel distribution — mu + beta·γ_E is). The declare var mgf JSDoc opened with "Gamma distribution moment-generating function (MGF)." (5/5 factory-style siblings open with "Gumbel distribution …"). Total: 13 sites, 6 files, +13 / −13 LOC.

Validation

What was checked:

• Structural feature extraction across all 15 members (file tree, package.json shape, README headings, test/benchmark/examples file naming).
• Semantic feature extraction (public signature, validation prologue, return kind, doc-comment prose, JSDoc shape, dependencies) across the 14 function-style packages, plus the JS/TS/C documentation prose.
• Independent validation passes against the surviving outlier:
  1. Opus semantic-review on mgf's doc-comment drift → confirmed-drift (parameter is named beta in code; mu is a location parameter, not the mean; Gamma distribution is a copy-paste artifact).
  2. Opus cross-reference against mgf's tests, examples, factory, native bindings, namespace re-exports, and any consumer importing the package → safe-to-apply (no test, fixture, or downstream consumer references the existing wording).

What was deliberately excluded:

• ctor's missing binding.gyp, manifest.json, native bindings, and ## C APIs README section — inapplicable to a JavaScript constructor with property accessors.
• mgf's and skewness's missing test/fixtures/julia/ directory — mgf's tests already exercise analytically known values; skewness for Gumbel is a parameter-independent constant (Julia ground-truth fixtures would be mathematically meaningless).
• lib/factory.js / lib/index.js only present in the six factory-style packages — minority pattern, not drift.
• The ## Notes README section in logcdf/logpdf — minority pattern reflecting genuine domain notes for those functions.

Other

This PR is the output of a per-namespace cross-package drift-detection routine. The full per-feature majority/conformance/outlier breakdown and per-agent verdicts are recorded in the local report at ~/drift-reports/drift-stats-base-dists-gumbel-2026-05-09.md.

Checklist

• Read, understood, and followed the contributing guidelines.

AI Assistance

• Yes
• No

How AI assistance was used:

• Code generation (e.g., when writing an implementation or fixing a bug)
• Documentation (including examples)
• Research and understanding

Disclosure

This PR was authored by Claude Code running an automated cross-package drift-detection routine. The routine extracted structural and semantic features from every member of stats/base/dists/gumbel/, computed per-feature majority patterns at a 75% threshold, and dispatched two independent Opus validation agents (semantic review, cross-reference safety check) against the surviving findings. The single advancing finding produced this 13-site, 6-file, behavior-preserving prose normalization.

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/gumbel/mgf	$\color{green}296/296$ $\color{green}+100.00%$	$\color{green}20/20$ $\color{green}+100.00%$	$\color{green}4/4$ $\color{green}+100.00%$	$\color{green}296/296$ $\color{green}+100.00%$

The above coverage report was generated for the changes in this PR.