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.

[ks27]

Less round corners would be better, and one color for the box outline...

[maveonair]

I think the new Nova design could be more restrained on desktop:

- Colors and gradients: They make the browser feel more playful than I would expect from a tool I use for professional work. I would prefer a more neutral default design
- Border around the content: The separation between the navigation bar and page content adds visual noise. A flatter, cleaner transition would feel less distracting
- Prominent call-to-action buttons: Buttons like "Sign in to Sync" draw too much attention. I would prefer secondary actions like this to be more subtle

Overall, I would like Firefox on desktop to prioritize a clean, calm interface that stays out of the way of the content.

[mave]

I much prefer the new settings, but for general use, there is just so much wasted space with rounding all of it. I personally have not, nor will I ever, care for vertical tabs. Tab groups are great, but not a huge fan of it in Nova - I much prefer the old style.

What someone else said earlier, I find truth in: the browser is meant to get out of your way to do the best /browsing/ of websites, and should therefore be as small as a part of it.

[sosasees]

I found one annoying Color Choice with the new default Theme:

The red-blue on off-white Icons (in light Mode) look too low-Contrast.

It is somehow the most painful to look at Color Scheme in any professionally made UI so far. Please make the Icons black, just like the Text is.

This Icon Color passes WCAG 2.0 Level AA but if a User says it’s painful, that’s more important than a computed Test Result.

[honnk]

I swear we used to be able to edit the url for passwords. Now, you can only edit the username and password entries. If you mistype the url, you have to create a whole new password. Annoying.

[JayceeBaron]

I loathe the rounded corners and Android pill-shaped buttons. I have an older laptop with square corners and won't buy a new one until the rounded corner fad goes away. It should always be a choice, not forced upon us. I will drop Firefox/Mozilla after all these years (since Netscape) if we aren't given appearance options.

[Blubb55]

Thank you so much for re-adding density mode again, (even if it could be even more dense for me). Also, I really love the new logo choice. I really like the older logos. No idea how I unlocked the bonus ones though (really nice Idea!) But: Please add at least some sort of a custom option aswell. Personally I prefer the previous 2017 Nightly one. Maybe I'd add a Kit in nightly-colors for a change.

While I really like compact mode, it should also apply to tab spacing. I use tabs vertically, but no matter if I use compact or touch mode, the spacing vertical spacing is the same. The height of the tabs itself change, but effectively the spacing is the same, still.

edit: also noticed, no matter if condensed or touch, the spacing does not change at all and stays very spacious on multiple places, like the suggestions on the URL-bar / awesomebar. the amount of suggestions etc is reduced while the height of each suggestion is greatly increased. Please, let "compact" be compact everywhere. 

Now that I'm used to the "old" slightly rounded tabs which I like, this amount of curvature is IMO way too much. I mean, you could implement a setting to choose between "hard edges, smooth edges, circled edges"

Also, a significant change for the container functionality was also added with the new tab designs: 

(mind, I use vertical tabs) previously the color indicator which told you which container a tab was loaded in, was on the side of the tab. With this change, it is now on the top. Please, change it to the sides again - when optimizing the compact mode, and it being possible that tabs can move closer to each other, that indicator could cause some confusion aswell. 

While, sure, that line on the top is easier to see, but it is harder to differentiate when having a lot of vertical tabs, no matter if the tab spacing will be compacted or not. If even, increasing the line width would also be a possibility.

left side: nightly, new design;

right side: firefox release, old design

[cybbro]

Why are there gaps between web content and top bar? Feels like wasted space. Why do tabs have gaps? Why are they floating? More wasted space. Why are they rounded like pills, more wasted space. Especially for users who have many tabs open those pills barely display any tab information making it harder to find tabs... I am not a fan of this rework, it seems the team is prioritizing fancy gaps and wasting space rather than make it readable and space efficient. I like the compact mode in general, it's a good addition, but those tab pills are becoming microscopic, hard to spot the tab I need.  Please team, don't make changes just for the sake of it. Change things if they actually add functionality or convenience.

Look at those pills - yuck!

[sosasees]

I noticed that the Pill Shape doesn’t actually make the Tabs smaller or more spaced apart
but it still makes the Tabs look constrained into a Space that is too small, so the Shape should be reverted.

[sosasees]

Yes, the ridiculous outer Window Border is gone in all Densities 😃

Now i wait for the bottom two Corners of each Tab to be sharp
so that they look like Tabs and contrast the Address Bar.
I want this Effect for horizontal Tabs and for vertical Tabs.

[sosasees]

Photo Edit of 2 concrete Ideas, of how i think Firefox Nova could look much better:

 

• Tabs with traditional Shape of horizontal Paper Tabs (i believe this exact Shape works just as well in vertical Tabs)
• Simpler Border between Browser UI Panels: Thinner and only one Color

If you struggle to spot the Difference, this Graph highlights every Pixel that changed in my Edit:

 

[sosasees]

Seriously, please consider these Changes. Seeing them in my edited Screenshot gives me strong positive Feelings:

• The bottom-heavy Shape of the Tabs gives the main Interface a really nice Sense of Weight that i sorely miss when using Firefox Nightly right now.
• The simpler Border makes it much easier to see where each Browser Section begins and ends, and it also makes the Sections feel unified rather than isolated.

[JBrickelt963]

As for the search bar, it looks rather good; I’m not quite as keen on how it looks in the app’s burger menu, but again, it’s acceptable. The ‘horizontal’ tabs are fine too, but clearly, when it comes to the collapsed vertical tabs… I think that’s going to bother me for a long time. As for the expanded vertical tabs, it’s much the same as the search bar – they look quite good. That said, I hope this new look is genuinely optional and easy to disable. I must admit I really liked the slightly rounded rectangular bubbles, and they’re still a pleasure to use. Perhaps offering a default setting for the rounding whilst allowing everyone to adjust the percentage of rounding would be a good compromise.

[shifter]

I overall love the design. I don't have had any issues in the past couple of days and really like the new modern look. I know it's subjective and I've also seen people that don't like the new design, but I think it brings the browser more inline with what most of the people like, and I think it's kind of the point to make Firefox more appealing so that it stays competitive and more people use Mozilla products. I like that Firefox gives me choices for what I want to toggle on and off and as long as that stays the case I don't see why certain defaults should be a problem.

The only thing that I'd say would (for now) that would be a nice bonus is that the spell check is as easy to use and download new dictionaries as the translation feature (now I have to hunt for dictionaries while the translation can be downloaded in the settings).

[Dodos]

I appreciate the fact that you are trying to refresh Firefox, since some people might have an idea that a webbrowser that doesn't change looks every 2-3 years is outdated.

Pro: I like the presentation of the main navigation interface, even though the pill-ness seems slightly exaggerated and I fear that it will require more padding to make them look "perfect". It looks fresh though.

Cons: As of now the border from the favicon to the borders of the pill are not a lot and make it look a bit "busy" and inconsistent from the rest. When clicking the hamburger menu, the round-ness seems to be very busy and an entire new design language that isn't really compatible with either what Microsoft is pushing today or any desktop environment on linux, maybe besides Gnome. The round-ness of the context menu makes me think of the recent "improvement" Microsoft did with Edge with a rounded frame in all pages. It looks atrocious and wastes space and clutters the view.

I will however always use Firefox, since it is the bastion against Chromium based monopoly. 

[Cooldash]

Really, this is so peak and awesome. I absolutely love it!! Suggestion: maybe give pill like edges whatever you call them to the other tabs but like darker or something, but as i type this i realize its probably not that good of an idea 🙂

[Leo_sk]

I used the mica styling in windows 11 for firefox through about:config entry. This new style doesn't support it. The default colours are not to my liking and can be changed, but i would still prefer transparency and blur.

Also, the tabs look thin relative to address bar/toolbar, especially the active tab.

There is also an attempt to give the appearance that toolbars and sidebars lie over a base chrome, which just makes everything appear busy, without any significant utility.

For now, i will revert to original design as long as possible, and maybe resort to userChrome when its not

[Minus]

why are my themes breaking when i select another window this just started today plz fix

[Neon1]

Did they remove the spacing around UI elements? I like this way more. Also I love how it integrates better with my GTK theme.

[breakingspell]

Yes 👏 Done here and here 

This was because of the direct feedback from the community, otherwise they would have never known their design was a no-count from the start. Really glad the message got through. 

[sosasees]

I finally know why i hate the new rounded Tabs:
Square Favicons appear to cut into the rounded Tabs

Firefox for Android solves this by cutting the Favicons into a Circle Shape
but i don’t really like that Solution either
because Web Designers don’t see it coming, leading to awkward Icon Shapes.

The Tabs should just have a Shape that lets Favions normal Shape breathe.

[sosasees]

By the Way, i still dislike the purple Toolbar Icon Color in the default Theme because it looks low-Contrast.
Copying the purple Toolbar Icon Color from the Dusk Theme into the default Theme would look much better without resorting to black.

[sosasees]

Nightly 157 looks the same, so the Design has not improved 🙁

[MusicBoxTW]

I really dislike the new Nova shortcut layout.

I had my Firefox homepage carefully organized exactly the way I wanted it, with 8 shortcuts across and 4 rows. I use that page constantly, and over time the position of those shortcuts became muscle memory. I could practically navigate it without thinking.

Nova has compressed everything into a much narrower 6-column grid, disrupting that organization while leaving a huge amount of completely unused space on either side. It feels cramped and cluttered for no apparent reason.

What makes this especially frustrating is that my topSitesMaxSitesPerRow preference is already set to 8. Nova simply ignores that layout preference and decides that I should have 6 columns instead.

Please give users control over this. If there is enough screen space for 8 columns, let us use 8 columns. Better yet, respect the existing preference rather than overriding a layout that users may have spent years organizing around.

For now I've disabled Nova and immediately got my 8-by-4 layout back. The difference is enormous.

[Filippo]

I filed a new discussion and a bug regarding some Nova glitch.
Hope someone in Mozilla consider my point of view.

[akayanni]

Ashley, ignoring my minor dislike for this gradient colour...

This is what matter to me as of today...

1. the annoying AI floating stars, love AI and hate this implementation
2. improving the sandboxing so that it is easier to share data outside the sandbox
3. better WASM performance and support
4. improving the chrome reduction for web apps, that would be my #1 improvement request

Brave versus Firefox... I'd want less chrome than Brave. 

[sosasees]

How do you install Web Apps in Nightly 157?

I found no Functionality related to Web Apps.

[Agentvirtuel]

Hello

Is it your question https://support.mozilla.org/en-US/kb/web-apps-firefox-windows
Please, check, the preference, browser.taskbarTabs.enabled
https://connect.mozilla.org/t5/ideas/extend-pwa-support-to-linux-and-macos/idc-p/135231/highlight/tr...

[sosasees]

[Web Apps] is available only on Windows. It will not appear on macOS or Linux.

Thanks, that explains it. It’s not on Linux.

Before Web Apps appear on Linux, i want the Address Bar stripped from Web Apps.

Web Apps in Firefox for Android have “Copy URL” and “Refresh” Buttons hidden in a Live Notification.
Similarly, Web Apps in Firefox can have the same Buttons hidden in a Hamburger Menu in the Title Bar.

Brave versus Firefox... I'd want less chrome than Brave.

That’s not realistic because Brave Web Apps already have minimal Chrome.
It’s just a Title Bar, and you can’t remove it without also removing the Title Bar Buttons and the Ability to move the Window.
So Firefox Web Apps should match the minimal Chrome of Brave Web Apps instead.

[sosasees]

Side Note: I would find the “Move the web apps back to Firefox” Button useful on Firefox for Android.
Add “Open in Firefox” to the Live Notification, please.

[akayanni]

Using Linux Fedora, that's what the screen shot is. 

IMO even Brave doesn't go far enough. 

[akayanni]

Actually I can go further, but it isn't via a Firefox trick. Perhaps could be put into Firefox for Linux. It could certainly be better documented, we did a bit of research to make this happen. 

Smart Editor - a chrome-less web-app window, and what we'd like from Firefox

WHAT WE DO TODAY
Smart Editor is a desktop suite of web apps (raster and vector editors, a notes
app, mail, messaging, a terminal, a universal viewer). We wrap each app as a
native window with a single embedded webview, so the page owns the entire
viewport - no browser chrome at all: no title bar, no address bar, no tabs, no
menu. On Linux we do this with tao + wry, whose webview is WebKitGTK; on Windows
it is WebView2, on macOS WKWebView. The only control surface left is the OS title
bar, and even that is one flag from gone. There is no Gecko option in this stack -
Mozilla ships no embeddable, chrome-less Gecko runtime, so a Gecko-backed app
window is not possible today without a full Firefox window.

WHAT FIREFOX ALREADY HAS (Taskbar Tabs / "Web Apps")
Firefox's Taskbar Tabs feature (Settings > Labs, experimental) does much of this -
a simplified, site-styled window pinned to the taskbar:
- Windows: supported (the furthest along).
- Linux: available but early - unsandboxed and under Flatpak, disabled by default.
- macOS: not supported. The stated reason is architectural: Firefox web apps run
in the same process and profile as the browser, and macOS's Dock assumes one
app = one process, so it cannot tell them apart.

THE INSIGHT WORTH ACTING ON
That macOS blocker - shared process, so the Dock cannot distinguish apps - is
exactly the problem a per-app-process shell does not have. Each of our apps is its
own OS process (one native window + one webview), so the Dock/taskbar sees them as
distinct applications automatically. If Firefox launched each web app as its own
process (or a lightweight per-app content process bound to a distinct bundle
identity), the macOS Dock problem largely goes away.

WHAT WE'D LIKE
1. Bring Taskbar Tabs / Web Apps to macOS. The per-app-process model above is the
way through the Dock limitation you have hit.
2. Go further on chrome removal - a true chrome-less app window: no address bar,
no standing menu. Collapse the essential controls (menu, minimise, close;
back/forward/reload) into the title bar and reveal them ONLY while a modifier
(Meta/Super) is held - release and they hide. Chrome-less by default; controls
reachable on demand, not standing chrome.

The nearest existing Firefox options fall short of point 2: kiosk mode is
all-or-nothing (no reachable controls), and userChrome.css is an unsupported,
brittle hack that cannot do the reveal-on-modifier behaviour.

REFERENCE
We built a working prototype of exactly this - a native window with decorations
off and a single webview (tao + wry), where the controls live in a title bar that
appears only while Meta/Super is held - plus a still image showing it. So the
target experience is something you can see and try, not just a description. Happy
to share both.

[akayanni]

I would definitely say that the over side of WASM was control of the chrome. What we have working here may or may not work on a different OS. And that means pita testing as we are 100% Linux. Feels like an opportunity for Firefox to set a new series of industry standards. 

The Rust Leptos WASM apps we have build are snappy as. I'm not the first person to discover this. 

We want the application to manage the interface and not the interface to dominate the application. The more feature rich this can be the move "native" an application can feel.

[sosasees]

I would not want the Browser Title Bar hidden because then it’s not obvious how to reach the Browser Title Bar.

Prioritizing Style over Usability is never a good Idea. The Frustration of not finding unnecessarily hidden Controls when i need them always outweighs their superficial Beauty.

[Agentvirtuel]

As for me, Web apps Windows, Web apps Linux

Install Firefox on Linux
https://support.mozilla.org/en-US/kb/install-firefox-linux
As for me, System Firefox installation (for advanced users), that's my installation.

[Agentvirtuel]

Other illustration, Web apps Windows

Just a question, have you checked the preference, browser.taskbarTabs.enabled
https://connect.mozilla.org/t5/ideas/extend-pwa-support-to-linux-and-macos/idc-p/135231/highlight/tr...

1 - Go to configuration editor https://support.mozilla.org/en-US/kb/about-config-editor-firefox
2 - Enter a search term browser.taskbarTabs.enabled
You can double-click on the preference to set the value to true

[cephirosx]

looks like Nova is now turned on by default on Firefox Nightly 157, where is the option to change the roundness of the corners? I'll stick to using Brave if Nova hits stable without the option to change the corner rounding

[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.