Local History and Comparison answer a practical question: did this page get better, worse, or simply different since the last comparable scan?
This is one of the places where the extension has to be careful with language. Having history is not the same thing as having a usable baseline. The page may have changed route, scope, viewport, or filter state. The UI needs to say that plainly.
What this feature is for
Local History and Comparison answer a practical question: did this page get better, worse, or simply different since the last comparable scan?
Feature coverage
- Shows saved local history and the filters that affect what appears.
- Compares the current scan with a previous scan when the baseline is comparable.
- Opens previous scan details so the reviewer can inspect what changed.
- Clears saved history when the local record is no longer useful.
- Exports trend snapshots for handoff or release discussion.
- Keeps comparison language separate from current confirmed, needs-review, and coverage-gap counts.
WCAG and accessibility importance
Local History and Comparison supports WCAG work by showing whether accessibility evidence changed between comparable scans. It is not a WCAG criterion by itself, but it helps reviewers track regressions across criteria such as 1.1.1 Non-text Content, 1.3.1 Info and Relationships, 2.4.3 Focus Order, 2.4.7 Focus Visible, and 4.1.2 Name, Role, Value.
The important accessibility value is regression control. If a fix improves one area but breaks keyboard order, headings, or accessible names, comparison evidence helps the team catch that before release.
Technical notes
- History records are local-only and are not sent to a remote service.
- Comparison uses stored finding fingerprints and scan summary metadata to classify new, resolved, unchanged, and changed-risk evidence.
- Filters such as page scope, date range, and baseline state can make a table look empty even when older scans exist.
Desktop tutorial video
Where to learn more
Official A11Y Cat documentation: https://carlashub.github.io/a11y-cat-extension/