Take Project Nova for a spin in Nightly!

[AshleyT]

Hi there! I'm Ashley, Senior Staff Product Manager for Firefox. After months of updates on Project Nova, it's finally in Nightly, ready for you to see for yourself. We're modernizing Firefox from the ground up to ensure it remains a fast, secure, and highly customizable companion for today’s internet.

This is still early days, so you'll notice some rough edges — a few things may look unfinished or inconsistent for now. Keep your Nightly up to date to see the latest. 

As a reminder, the Project Nova updates include:

• Simpler navigation and a redesigned Settings experience, now live in release
• Refreshed tabs, icons, spacing, and browser surfaces
• More ways to make it yours, with rich new themes, wallpapers, and personalization options that let Firefox match your style.

We're grateful for all the thoughtful feedback we got on our earlier Connect post, on social media, and through user research. Based on what we heard, we've made some changes:

• We'll be experimenting with corner roundness settings for tabs to give you more options — coming soon in Firefox Labs.
• We brought back Compact Mode so there’s more space for web content and tabs
• We added more neutral standard theme options.

You can learn more in our blog post.

See it first in Nightly

Nightly is where this work takes shape in the open, and we wanted you to be among the first to see where it's headed. Since much of what’s changed so far focuses on the look of the interface, keep an eye out for how these layouts feel during your day-to-day browsing. We're aiming for a clean, intuitive experience —so please look out for anything that feels off, like icons, spacing, alignment, or how things hold up across themes, window sizes, different languages, screen readers, and keyboard navigation. If something catches your eye, we'd love to hear about it.

Download the latest version of Nightly to see what's new.

Something's not right? File a bug.

If you find visual or functional issues with the Nova style changes in Nightly, please follow these steps:

1. Click this link to file a Bugzilla issue. We're asking everyone to file bugs this way, so we can easily keep track of all issues reported.
2. In the bug, please add steps to reproduce the issue, and if possible screenshots or screencasts. Please don't add severity and priority to the bugs — our triaging teams will handle that.
3. You can see all Nova testing bugs filed here.

Have overall feedback? Let us know here in Connect.

Drop a comment here to let us know your thoughts and suggestions. Thanks for being part of this.

[akayanni]

On the theme, after looking at it, JUST NO! It looks like "I've just discovered the gradient tool". Simple fix, give us a tool so we can set the interface as we like it. A base theme with a few options and sliders.

If the "dark" theme I'm seeing is the same as others then NO. Do we really need themes for this in 2026? Couldn't part of the interface be covered with settings? Flexible ones.

[sosasees]

I hate the Gradients too. They give Firefox a lopsided Sense of Weight.

The right Side feels much heavier than the left, which is just wrong.

[akayanni]

Ashley,

I'm not sure what the usage is beyond myself. We try to transfer any data we can get for logs and AI use. Hence "DomEyes". I think this is serious enough for further consideration so I've set it out and had Claude document what we are doing. 

We want to be able to fully manage the browser via the extension. It's part of application development and testing. We want to send screenshot of before, on roll over and clicks. There a plan. 🙂 Not sure it this covers everything. 

Because FF was a pain, we have 2 versions, the plugin and the built into the sites. I can tell you from using the code base we have this is a must have feature. I think there are some real wins in this for FF.

Smart Editor — a Firefox extension that bridges the page to a local AI agent, and what we'd like Mozilla to protect

**Context:**companion to the chrome-less app-window note. Same project (Smart Editor, smarteditor.io), different surface. Where that note was about running web apps as chrome-less native windows, this one is about a Firefox extension we built — "AI Dom Eyes" — that gives a local AI agent eyes on any web page and moves that data to a local daemon on the user's own machine. The mechanism works today and leans on things Firefox does better than Chromium — but it also sits in the path of two changes (MV3, Private-Network-Access) that could quietly break it. The ask is: help us keep a sanctioned, permission-gated version of this alive.

---

TL;DR

A Firefox Web Extension captures a live page (console, network, DOM, element inspections, the user's text selection) and POSTs it to a local service on 127.0.0.1— a small daemon (hed) running on the same machine — where a local AI coding agent reads it back. No account, no login, no cloud round-trip; the page's data never leaves the device. It uses sidebar_action(a Firefox strength Chrome lacks) and an MV2 persistent background page. Both the localhost bridge and MV2 are under pressure industry-wide. Our ask: a first-class, user-consented way for an extension to talk to a local service that the user is running — so this local-first pattern survives MV3 and Private-Network-Access instead of being collateral damage.

---

1. What the extension is

"AI Dom Eyes" (Manifest V2, Firefox; browser_specific_settings.geckoset). Its own description: "Gives an AI coding agent eyes: captures a live page (console, network, DOM, element inspections) into a local store the agent can read. In development, open source."

• Sidebar UIvia sidebar_action— the panel lives in Firefox's sidebar, not a popup. This is a genuinely Firefox feature; Chromium has no sidebar_action.
• Content scripts(document_start+ document_idle) capture console/network/DOM and an element inspector, on <all_urls>(our own origins are excluded— they're already instrumented).
• Context menu: right-click a text selection → "send selection to agent."
• Persistent background page("persistent": true) that owns the capture streams and the bridge.
• Permissions: <all_urls>, tabs, activeTab, storage, downloads, clipboardWrite, contextMenus.

2. How the data actually transfers (the whole mechanism)

Two paths, both local-only:

1. **Extension → local daemon over loopback.**The background page POSTs captured context to a small local bridge:

// background.js — pushToHed()
fetch('http://127.0.0.1:9123/atom', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify(Object.assign({ cmd: cmd, uid: 1 }, data))
})

127.0.0.1:9123is hed— a Rust daemon on the same machine where every capability is a small JSON-in/JSON-out "atom." The agent reads the page back with an atom call (debug.context {uid:1}). If no bridge is running, the fetchfails silently and the extension keeps everything in its own in-addon store. No remote endpoint is ever contacted. 2. Clipboard.navigator.clipboard.writeText(...)(the clipboard Writepermission) copies a captured selector / value / context so it can be pasted straight into a local terminal or agent tab.

That's it. The "data transfer" is browser page → user's own localhost service, plus the clipboard. Nothing leaves the device.

3. Why this is a Firefox story, not a generic one

• **sidebar_action**is a first-class Firefox surface and the natural home for an "agent's view of the page." Chrome only recently, and differently, grew a side panel; Firefox has had this cleanly for years. The extension is better on Firefox.
• Firefox's local-first / privacy brand is the exact fit for "the page's data goes to a daemon on your machine, not a cloud." This is the browser whose users want that.
• MV2's persistent background page is a clean model for a long-lived capture/bridge; Firefox has been the sane, developer-respecting holdout on the MV2 timeline.

4. What's at risk (why we're raising it now, not later)

The mechanism depends on two things the whole industry is tightening:

• **Manifest V3.**The persistent background page goes away (event pages / workers), and the host-permission and background models change. A capture-and-bridge extension that assumes a long-lived background context has to be re-architected. We'd like to do that with a known-good target, not guess.
• **Private Network Access / Local Network Access.**A document or extension fetch-ing 127.0.0.1is exactly the pattern browsers are moving to gate (Chrome's PNA; the W3C Local Network Access work). And rightly so — a random extension with <all_urls>reaching localhost is a real malware vector. But the same brushstroke that stops the attacker also stops the legitimate, user-run local agent. If Firefox follows without a sanctioned path, this breaks.

We are not asking Firefox to keep the loose pattern. We're asking for the supervised version of it.

5. The ask

A first-class, user-consented "connect to a local service" capabilityfor Firefox extensions:

1. **A permission-gated loopback bridge.**An explicit permission (e.g. a localnetwork/ localhost-scoped grant the user approves at install or on first use) that lets an extension talk to a declared local port/service — so the user's own agent works, while a drive-by extension still can't silently probe localhost. Survive Private-Network-Access instead of being caught by it.
2. A clear MV3 path for a capture-and-bridge extension— guidance (or a supported primitive) for a long-lived local connection under the event/worker background model, so "give a local agent eyes on the page" remains a buildable, reviewable extension pattern after MV2 sunsets.
3. **Keep sidebar_actionfirst-class.**It's the right home for this and a Firefox advantage; we'd hate to see it deprecated toward a Chromium-shaped side panel.

6. Why Mozilla specifically should want this

Local-first AI — an agent running on the user's machine, reading the user's browser, with nothing sent to a cloud — is a category Firefox is uniquely positioned to own. The privacy story writes itself: your pages, your agent, your device. The risk is that generic anti-malware hardening (MV3 + PNA), applied without a sanctioned local-agent lane, makes Firefox the browser where local-first AI can't work — the opposite of where its brand points. A supervised loopback permission turns a lurking break into a headline feature.

---

Appendix — the two halves of one picture

• Chrome-less app windows(the other note): running web apps as native, chrome-less windows; today via tao+wry(WebKit), no Gecko option.
• **This note:**a Firefox extension bridging any page to a local AI agent over loopback + clipboard, using sidebar_actionand an MV2 background page. Together: *local-first web apps, and a local agent wired into the browser.*Both want Firefox to be a first-class host. This one is the more time-sensitive, because MV3 + PNA have a clock on them.

[akayanni]

This is the coded into the site version.

[Cooldash]

nice ai

[qwryu]

With the gap removed in Nova's latest design, it's lost its distinctiveness and now looks like every other product.

[sosasees]

It should be possible to make Firefox Web Apps (Taskbar Tabs) slimmer
because right now, they have the widest minimum Width.

Screenshot of the same Website opened in 3 minimum-Width Firefox Windows on Linux Mint. From left to right:

• Firefox Window from Linux Mint Web Apps has the second-widest Window
• Regular Tab in Firefox Nightly has the slimmest Window
• Web App (Taskbar Tab) in Firefox Nightly has the widest Width

I need Web Apps to slim down to 640px — one Third of my 1920px wide Screen — at 100% System Display Scale

[Joncarter232]

I completely agree. The recommendation system should give more weight to our feedback and let users customize the categories they actually want to see. A preference hierarchy or category toggle would make the homepage much more useful. Features like Menu with Prices could also be easier to discover when users have better control over their content preferences.

[SunnyTsu]

Wow, that’s really great! I love the pill-shaped design and the rounded corners — it makes the whole thing feel much cleaner and more modern. Will you also be adding an Australian-style look? I think that could look really nice with this design as well. Curious to see how it turns out!

[akayanni]

Better... so glad the + has moved back. Just so you know someone noticed. And it looks better in black/gray theme.

The pill shape is "current". I'm whatever on it.

Just default to the black/gray (smoke) theme and this is all good. I tried a few of the others. Here lots of gray is good for eye color balance.

The rounded corners in the drop-down menus are OK. The rounded corners in the hamburger menu are excessive and should match the drop-downs.

Hiding all of it until a rollover of the titlebar would be good. I do everything to create complex designs that look simple and focus the user's attention. It's on the edge of ego for Firefox to think their interface is what I want a client to look at. It's taking up real estate between me and my client.

I can target FF without an interface and be happy. I can promote it as "this site is best viewed in Firefox" if I can hide the Firefox junk. Add hide to the theme. Show menus, tabs and URL bar on rollover of title.

I'll bet if you do, every other browser will copy the feature. You would get a short marketing window to say "Firefox, the browser that respects the work of web developers by disappearing."

And we don't have your choice of defaults and use of pills competing with our web designs.

Then you have an outcome from the whole theme project you can write spin about.

AI changes who your consumer is; the developer:client ratio. Move people making more things and needing a standard platform to run them on. Firefox is a perfect choice. WASM is the go. Firefox delivers on DOM processing and console. You could lose that position to Brave. There are some controls AI has in Brave that allow it to do testing. There are a lot of reasons to stop using Firefox and not a lot of reasons to stay. Then there is the RAM suck.

Mozilla is not getting enough out of existing work. I think the big question is...

What has been built for Firefox that could be better shared with developers to deliver clients first-class websites and apps?

Outcome: This site works best in Firefox

You have Sync, we like to sync things too. Plugin panels, shame they are ugly as sin. Ability to write files from various sandboxes.

I don't like what we are doing, developing with Firefox to deliver via Tauri (WebKitGTK/Chromium) just to control chrome and run the apps locally. Mozilla could start a project to create Firefox Tauri. It would be better if what is required was built into Firefox. At worst it would need a registry to manage the security of what was previously a sandbox. There are 4+ WASM engines providing a surface.

Firefox is a browser, we understand the history. Now we need Firefox to be a surface. Disappear the interface is part one and easy. Part 2: enable the use of the sidebar that integrates with site view and doesn't chrome off it. Part 3: expose skills as per Tauri to be a desktop app. I can give you a list of why-Tauri — what we used and what choices we had. We can pull any info that is useful from the build.

When we get to it, we are using a Tauri overlay on an Iced workspace, with development "on the web". We want one system all the way. Not some "experiment" as per previous efforts! A commitment to code it into Firefox core. The only way to deal with being squashed between WASM projects on the left and Chromium projects on the right is to go volcano on them.

I'll get Khalid to add it to the broader response we are putting together.