One file, no browser APIs
The scanning engine ships as a standalone bundle with no dependency on the extension APIs. Any runner that can evaluate a script in a page — Playwright, Puppeteer, Selenium — can inject it and read the report back as JSON.
The same rules, the same results
This is not a reduced rule set or a second implementation. A finding in CI has the same rule id, the same selector and the same suggested fix as the one you would see in the panel — which is what makes “reproduce it locally” a real instruction rather than a hopeful one.
Start with the page you are on
Install the extension, press F12 and open the Accessibility tab. No account, nothing to configure, and nothing leaves your machine.