YuzuFox

Hardened, zero-bloat Firefox. Compact, pywal-themed UI.

YuzuFox transforms Firefox into a privacy-respecting and performance-optimized browser with a compact two-row UI that auto-tints to your wallpaper, securing your data without breaking sites.

Overview

File	Purpose
yuzu.js	System autoconfig (840 lines): privacy, performance, UI cleanup
userChrome.css	Compact two-row UI — 16 px tabs + auto-hiding navbar, pywal-tinted colors
policies.json	Enterprise policy: uBlock Origin auto-install, enforced privacy
install-settings.sh	Install/uninstall yuzu.js + policies.json (Auto Region/Language Filter via offline timezone detection, not IP-based) (requires sudo)
install-css.sh	Install/uninstall userChrome.css to Firefox profiles (user-level)

yuzu.js

Over 300 locked preferences covering:

• CRLite-only revocation — OCSP disabled; certificate checks offline via CRLite mode 2
• RAM-only cache — disk cache disabled; 1 GB memory cache, 3 GB media cache
• Zero background connections — all speculativeConnect, DNS prefetch, predictor flags severed
• Fingerprinting Protection — Firefox FFP, content script isolation, referrer trimming
• Safe Browsing disabled — delegated to DNS-level blocking
• Complete telemetry block — Normandy, studies, crash reports, coverage, activity stream all capped
• Mozilla bloat removed — Pocket, VPN, AI, sponsored content, promotions all disabled
• WebRender forced — GPU compositing, hardware video decoding, Skia font cache

policies.json

Enterprise Policy auto-installing uBlock Origin with pre-configured filter lists, enforcing privacy settings, and removing Mozilla messaging.

Third-party data sources: policies.json configures uBlock Origin to fetch filter lists from:

• uBlock Origin built-in lists (maintained by uBlock developers)
• EasyList / EasyPrivacy (community-maintained ad blocking lists)
• DandelionSprout's Legitimate URL Shortener (anti-tracking list)
• Region-specific filters (injected at install time based on timezone)

These lists are fetched directly by uBlock Origin at runtime, not by YuzuFox itself.

userChrome.css

~500-line stylesheet with a compact two-row layout: 16 px pixel-dense tabs (Maple Mono NF / JetBrains Mono Nerd Font) and an auto-hiding navigation bar that slides in on hover or URL bar focus. Colors are pulled live from pywal via @import of ~/.cache/wal/colors.css — run wal -i <wallpaper> and restart Firefox to re-tint the whole UI. Machines without pywal fall back to a fixed palette, so the layout never breaks.

Also includes: zero border radii, transparent URL bar, debloated navbar (back/forward/reload/home/library buttons removed), hidden tab close buttons, no window controls, container indicators shown via tab title color, and full theming of menus/popups, selection and scrollbars. The active tab is tinted orange at 30% opacity.

Install

Settings (requires sudo)

curl -sSL https://raw.githubusercontent.com/KabosuNeko/YuzuFox/main/install-settings.sh | bash

Css (user-level)

curl -sSL https://raw.githubusercontent.com/KabosuNeko/YuzuFox/main/install-css.sh | bash

Note: After installation, go to about:config and set toolkit.legacyUserProfileCustomizations.stylesheets to true.

Optional (pywal colors): install pywal (pip install pywal) and run wal -i /path/to/wallpaper, then restart Firefox. Without pywal, the default fallback palette is used.

Dry-run: Run install-settings.sh --dry-run or install-css.sh --dry-run to preview changes without applying them.

Uninstall

Settings

curl -sSL https://raw.githubusercontent.com/KabosuNeko/YuzuFox/main/install-settings.sh | bash -s -- --uninstall

Css

curl -sSL https://raw.githubusercontent.com/KabosuNeko/YuzuFox/main/install-css.sh | bash -s -- --uninstall

Credits

yuzu.js draws inspiration from Betterfox, Arkenfox and cachyos-firefox-settings

userChrome.css draws inspiration from firefox-qutebrowser-userchrome