Mozilla is quietly working on a new privacy feature for its browser that could give Firefox private browsing an edge over its rivals. According to reporting from Neowin, the company is developing a way to make private browsing more private when you step away from your computer — something Chrome and Edge still don’t offer on Windows.
Here’s what we know about the feature, how it might work, and why it matters for anyone who cares about protecting their online activity in shared or public settings.
What Firefox private browsing could gain
The core idea is simple: Firefox would detect when you’ve physically stepped away from your machine and take action to lock or shield your private browsing session. The goal is to stop someone from walking up to your unlocked computer and scrolling through your history, open tabs, or signed-in accounts while you’re gone.
As of now, Mozilla hasn’t released full technical details about exactly how this will work, so much of what’s being discussed remains speculative. What’s clear is that the feature targets a specific, everyday vulnerability — leaving a private window unattended in an office, coffee shop, or home where multiple people share a single device.
Private browsing mode already prevents Firefox from saving your history, cookies, and site data once you close the session. This new layer would add protection for the window of time you’re actually away from the browser, closing the gap between “private” and “unattended.”
How it might work in practice
While Mozilla hasn’t confirmed the mechanics, features like this typically rely on detecting inactivity or integrating with your operating system’s own lock screen. On Windows, that could mean Firefox waits for the PC to lock after a period of no input, then hides or locks its private windows accordingly.
Another possibility is that the feature ties into Windows Hello or the system’s presence detection, locking the browser the moment it senses you’ve left your desk. Mozilla has historically experimented with similar ideas, including options to lock Firefox behind a PIN or password, so this would fit into a broader pattern of giving users more granular control over who can see their data.
It’s worth noting that any such implementation would need to balance security with convenience — you wouldn’t want your browser locking itself every time you stand up to grab a coffee. The exact thresholds and user controls will matter a great deal once the feature ships.
Why Chrome and Edge fall short here
The reason this feature is drawing attention is that neither Google Chrome nor Microsoft Edge currently offers an equivalent on Windows. Both browsers include private browsing modes — Incognito in Chrome and InPrivate in Edge — that stop local saving of your activity, but neither automatically locks or shields those sessions when you step away.
This leaves a real gap for users who browse privately on a shared or public machine. If you close your laptop lid or walk away for a moment, your private tabs remain visible to anyone with physical access to the computer until you manually lock the screen yourself.
That gap is precisely why a native Firefox implementation could be meaningful. It would be one of the few areas where Firefox pulls ahead of its two biggest competitors on the Windows platform, reinforcing the browser’s long-standing positioning as the privacy-focused alternative.
What this means for you
If you regularly browse privately in shared spaces — an office computer, a library terminal, or a family laptop — this feature targets a real, everyday risk. Right now, the only thing standing between your private session and a curious coworker is your own discipline to lock the screen (Windows + L) before you leave.
With Firefox’s approach, that protection would become automatic rather than something you have to remember. Even in its early stages, it signals where Mozilla wants the browser to go: treating privacy not just as a setting you toggle, but as an active defense that responds to your physical surroundings.
Of course, no browser feature can fully replace basic situational awareness. If you’re worried about someone watching over your shoulder, no amount of software will replace glancing over it. But automating the lock reduces the chance of a simple, honest mistake turning into a privacy breach.
How to get it
Since Mozilla is still in the early stages of development, there’s no date to expect this feature and no setting to enable today. If you want to keep an eye on progress, the best approach is to follow Mozilla’s official channels and the Firefox changelogs as new builds roll out.
In the meantime, you can already get comparable protection by enabling Firefox’s built-in options to require a password when launching the browser, or by simply getting into the habit of locking your Windows machine (press the Windows key + L) whenever you step away. Those workarounds aren’t as seamless as an automatic lock, but they close the same gap today.
As always with features in development, details can change before launch. We’ll update this story as Mozilla shares more concrete information about the feature, including any release timeline.
Source: Neowin
Over to you: Would you trust a browser to auto-lock your private tabs when you step away, or do you prefer locking the screen yourself?
