Contribute
The most useful contribution is a precise error report: which module, which equation or sentence, what is wrong, and a source or a derivation that shows it.
Report an error
Every module page has a "Report an error" link that opens a GitHub issue titled with the module number. Quote the equation number, for example (15.4), or the section number, and say whether the problem is a wrong number, a sign or factor-of-two, a misattributed citation, a figure that misleads, or a script that fails. Confirmed errors are fixed and listed on the errata page.
Suggest or write content
Open an issue first for anything larger than a fix. New or changed module content follows the authoring guide (BRIEF.md in the repository): structure, accuracy rules, provenance badges, MathJax markup and the MATLAB rules (base MATLAB only, runs unchanged in Octave 8).
Quality gates
Every pull request runs two checks: the render check opens every page in headless Chromium at 1280 px light and 400 px dark and fails on JavaScript errors, overflow, blank canvases, MathJax errors or raw TeX; the Octave job runs every MATLAB script with a time limit. Both must pass. Details are in CONTRIBUTING.md.