Antimony r2: 2 architectures, 2 package managers, new official builds, for a browser that says no thanks to AI content

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The short version

Antimony is a Chromium fork built by yubi-OS that refuses to ship AI-generated content to you by default. Today we cut our first real release: antimony-v153.0.8010.36-r2, with installable packages for four platforms, official optimized builds, and a signed release attestation. It’s free, it’s open, and it’s the first shippable piece of the browser stack we’re building for yubiOS, our FIDO2-first immutable operating system.

Grab it here:

Package	Arch	Size	SHA256 (first 12)
antimony-stable_153.0.8010.36-1_amd64.deb	x86_64	121 MB	3ffedd4165db
antimony-stable-153.0.8010.36-1.x86_64.rpm	x86_64	122 MB	cdfc72060e48
antimony-stable_153.0.8010.36-1_arm64.deb	ARM64	108 MB	1046f0f5c809
antimony-stable-153.0.8010.36-1.aarch64.rpm	ARM64	109 MB	5472c7a92a9d

Every package has its full SHA256 in the release notes. There’s also a release attestation (JSON) so you can verify what you downloaded is what the build pipeline produced.

What Antimony actually does

Chromium 153.0.8010.36 under the hood, with a provenance gate patched in at the engine layer. Concretely:

• AI-content blocking with a real UI. Three modes: off, soft-block (AI images get swapped for notices you can allow per page), and full block (navigations with AI-content evidence get an interstitial, like the safe-browsing page). Per-origin exemptions live in chrome://settings/provenance, not in a config file.
• C2PA inspection in-process. The gate reads C2PA manifests (JPEG APP11, WebP RIFF) inside the browser’s data decoder, no extension or external service. Images carrying an algorithmicMedia AI claim get flagged.
• The AI Mode surface is gone. No omnibox AI chip, no AI menu entries, no AI settings page. The kill switch sits at the eligibility check every entry point funnels through.
• A provenance chip in the omnibox. When a page carries AI-content evidence, a security-icon chip lights up. Click it and you land in the provenance settings.
• On-device AI model blocking is a separate toggle. If you don’t want the browser’s built-in Writer/Rewriter/Summarizer APIs available to pages at all, flip it off independently of image blocking.

The rule we hold ourselves to: the browser never claims “human-verified.” Classifier-only blocks need high confidence and stay user-overridable. That constraint is written into the repo’s CONSTRAINTS.md, not just the marketing.

What changed in r2

This is the difference between “we built something” and “you can install something.”

• Official builds. r2 is built with is_official_build=true: thin LTO, CFI, stripped binaries. The inner chrome binary ships with zero symtab sections. r1’s unofficial amd64 deb was 581 MB; the r2 official one is 121 MB.
• Four platforms. deb and RPM for both x86_64 and ARM64. The RPM targets are new territory for us, and the ARM64 packages build on real ARM64 hardware, not an emulator.
• Tested on real hardware. The amd64 package was installed and run on actual x86_64 machines before this release. Not a CI-green-and-hope.
• Release attestation. The release carries a provenance attestation asset, same supply-chain posture we apply to yubiOS images.

Why a browser for an OS that doesn’t exist yet

yubiOS is our planned operating system: immutable, bootc-based, with a hardware YubiKey as the root of trust at every boundary. Every trust decision in yubiOS is verified before it runs, nothing asks you to trust an author. A browser that lets any webpage present machine-generated content as human-made breaks that posture at the most-used surface on the machine.

So Antimony ships now, free, as a standalone offering. Use it on any Linux distro today. When yubiOS arrives, the browser already holds the same standard the rest of the system will.

What’s next

Signature validation for C2PA manifests (currently we inspect, not verify), TrustMark and SynthID detectors joining the stack, and the packaging follow-ups. The full patch series (0001 through 0022) is public in yubi-OS/chromium-provenance, pinned to the Chromium 153.0.8010.36 mirror.

Built by yubi-OS. Questions or wanna get involved: shant@omniteck.com.