The first tagged release since 1.0.0 (2018). Compare has been rewritten
underneath: a new waterfall engine, new visual-progress chart, a real
filmstrip, Core Web Vitals, render-blocking metrics, accessibility work,
and a modern build setup. Many of these changes shipped to
https://compare.sitespeed.io between releases — this entry consolidates
them.

Added

• Swapped the waterfall renderer from PerfCascade to
  waterfall-tools and added
  a WebPageTest-style blend slider that fades HAR2 over HAR1 on a shared
  time axis. A side-by-side / overlay toggle is remembered across
  reloads, and hovering a request highlights it in the paired waterfall.
• Page X-ray table grouped into sections (Content, Render blocking,
  Visual metrics, Core Web Vitals, CPU, First/Third party) with a Δ
  column that highlights regressions in red and improvements in green,
  plus a per-table "Only differences" toggle.
• Filmstrip section (when both HARs have one) with frames sampled from
  the VisualProgress change points, and a lightbox for full-size frames.
• Visual progress chart now shows per-HAR timing markers
  (First Visual Change, FCP, LCP, Speed Index) and a thumbnail strip
  under each line.
• Core Web Vitals row in the page X-ray table:
  First Contentful Paint, Largest Contentful Paint, Total Blocking Time
  and Cumulative Layout Shift (3 decimals).
• Render-blocking metrics from Chrome HARs (blocking, potentially
  blocking, in-body parser blocking).
• Long Tasks, Total Blocking Time and Max Potential FID under CPU.
• stripVersion configuration flag (and a checkbox on the start page)
  to ignore query-string version parameters when diffing requests for
  the same URL.
• Support for .har.gz HAR files via the browser's native
  DecompressionStream.
• Skip-to-content link, ARIA labels and visually-hidden table captions
  for screen readers.
• Comment slot for the request/response diff section
  (comments.requestDiff in the config file).
• First/third party support — PageXray now auto-detects the host page's
  party automatically, and the share of first vs third party requests
  is shown next to each row.

Changed

• Build tooling moved to Vite. The build output
  directory is now dist/, not build/. Classic compare scripts are
  served verbatim from public/ and version-stamped at build time so a
  new deploy invalidates any stale cached copies.
• Styling rewritten in plain CSS (Sass dropped) with a small design-token
  layer. The start page and result header were refreshed to make
  regressions easier to spot.
• Templates rewritten as plain JS template literals (Template7 dropped).
• Upgraded PageXray to 4.x.

Removed

• The service worker / Workbox offline support. A one-time cleanup
  unregisters any service worker still installed from older versions
  so the first reload after upgrading is fresh.