Waterfox G6.6.0

What's new in this version:

Highlights:
- Vertical Tabs with optional Tree view
- Private Tab button next to New Tab
- Automatic Tab Grouping (configurable)
- New Tab wallpapers, optional search bar and weather
- Firefox profile import (bookmarks, history, passwords, cookies, form data)
- WebGPU enabled; VP8/VP9 hardware acceleration for WebRTC
- JPEG XL support; improved MathML rendering
- Privacy‑friendly defaults (less promos, fewer speculative/remote fetches)
- Numerous UI refinements and performance improvements

New:

Tabs & Sidebar:
- Vertical Tabs: First‑party vertical tabstrip integrated into the sidebar, with customization options
- Tree‑Style Vertical Tabs: Optional tree layout for vertical tabs
- How to enable: Show sidebar → Customize sidebar → Sidebar settings → Vertical tabs → Tree vertical tabs
- Private Tab Button: Quick “New Private Tab” button next to the New Tab button
- Automatic Tab Grouping: New tabs can automatically open within your existing tab groups for a more organized session

Config (about:config):
- browser.tabs.autoGroupNewTabs: true/false (default: true
- browser.tabs.autoGroupNewTabs.placement: "after" (default), "first", or "last
- browser.tabs.autoGroupNewTabs.delayEnabled: true/false (default: false
- browser.tabs.autoGroupNewTabs.delayMs: milliseconds (default: 1000
- browser.tabs.autoGroupNewTabs.cancelShortcut: defaults to Alt+ (macOS) / Ctrl+ (Windows/Linux

New Tab Page:
- Wallpapers: Use curated solid colors, custom colors, or your own image
- Optional search bar toggle
- Optional weather widget (opt‑in; see Mozilla’s documentation for data usage details)

Migration:
- Firefox Profile Import: Import bookmarks, history, cookies, form history, and passwords directly from a Firefox profile
- Note: After importing passwords, restart Waterfox to apply changes

Web Platform & APIs:
- WebGPU: Enabled, including Web Workers support
- Web Share API: Native OS sharing integration
- Media: VP8/VP9 hardware‑accelerated decoding for WebRTC video calls
- MathML: Updated rendering
- Experimental/Behind‑the‑Pref features (availability varies)
- CSS Masonry layou
- Prioritized Task Scheduling AP
- DOM: CloseWatcher, H.265 in WebCodecs, Screen Orientation lock, improved Shadow DOM selection, Web Notifications action
- CSS: shape() function, font-variant-emoji, @scope rule, scroll‑driven animation
- SVG: SVG 2 getBBox, improved stroke bounds renderin

Improvements:

UI & Customization:
- Menubar styling and tab bar positioning refinements
- Default Proton colors aligned with system accent colors
- Compact density by default for tighter UI
- Status bar restored with hover link readout and widget area
- Layout flexibility: move tab bar (top above/below, or bottom) and bookmarks bar (top/bottom)
- Rich built‑in toggles for tab shapes, spacing, separators, icons, and more

Platform polish:
- Windows: Mica/backdrop effects where supported
- macOS: Titlebar/sidebar blending for a more native feel
- Default bookmarks updated with Waterfox‑related links
- Smooth scrolling: alternative smooth scroll physics implementation

Network & Performance:
- POST request efficiency: idempotency‑key headers enabled
- Cookies: CHIPS and schemeful SameSite support

Network optimizations:
- Disabled requests to 0.0.0.
- HTTP/3 ECN marking and IP family retry suppor
- HTTP retry with half‑open connection
- Windows: On‑demand loading of keyboard layouts for improved efficiency
- Rendering: Dynamic reflow roots enabled

Privacy & Defaults:
- Reduced promotions: Disabled mobile‑related promos and various third‑party promotional surfaces by default
- New Tab Page: Removed search shortcuts from Top Sites
- Extension security: Block picker opening from hidden extension pages
- Pointer Events: Restricted to secure contexts per spec
- macOS: Ctrl‑click no longer defaults to right‑click
- Speculative connections: Disabled when typing in the address bar
- Remote config: Disabled fetching of remote settings lists; bundled offline copies used instead
- A/B testing: Disabled and related code not packaged

Fixes:
- Private Tabs: No longer retain history
- Web Page Translations: Model downloads no longer blocked
- Passwords: Autofill works reliably again
- Screenshot tool: Restored in the context menu
- Duplicate Tabs: Opening a duplicate no longer produces two
- Classic extensions: Fixed compatibility so classic style extensions (e.g., TabMixPlus) can be installed again
- Theming: Various small polish fixes
- Stability: Resolved crashes on certain systems related to optimization flags