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MIT · Firefox add-on

webext-gmeet-unmirror

Hides the Google Meet presentation tile so full-screen sharing doesn't produce an infinite hall of mirrors.

View source ↗

Features

  • Local-only hiding — the tile is hidden with CSS visibility: hidden in your browser only; the outgoing screen-share stream is untouched, so remote viewers still see your full presentation
  • Only ever acts while you're presenting — two cooperating, local-only signals confirm it: a MAIN-world hook on getDisplayMedia for the transition, and a DOM check for the local "Stop presentation" control as the source of truth. Someone else presenting can never trigger it
  • Robust tile detection — the presentation is the largest visible <video>, resolved to its container via Meet's stable data-tile-media-id attribute (with a geometric ancestor-walk fallback); the self-view camera tile is explicitly excluded so your own face is never hidden
  • Popup control surface — an "Automatic" toggle (persisted, default on) hides the tile the moment you present, plus a manual Show/Hide button and status line that's disabled whenever you're not presenting
  • Alt+Shift+H shortcut — toggle manually without reaching for the popup
  • Collects no data — a single host permission (*://meet.google.com/*), no background worker, no network requests

Install

From Firefox Add-ons (remote)

Gmeet Unmirror on Firefox Add-ons

The listing goes live once the add-on clears AMO review — until then, install from source below.

From source (local)

git clone https://github.com/kud/webext-gmeet-unmirror.git
cd webext-gmeet-unmirror
npm install
npm run build

Load it in Firefox: about:debugging#/runtime/this-firefox → Load Temporary Add-on → select manifest.json (or the built package in web-ext-artifacts/). Temporary add-ons are dropped on restart and must be reloaded after every change.

Usage

Open any Google Meet call at meet.google.com and share your whole screen as usual — the extension only ever activates while you are the one presenting:

  1. With Automatic on (the default), the presentation tile hides itself the moment your share starts.
  2. Prefer to control it yourself? Turn Automatic off in the toolbar popup and use the Show/Hide button there, or press Alt+Shift+H, whenever you want to toggle the tile.
  3. The button and shortcut are disabled/inert whenever you're not presenting — there's nothing to toggle until you are.

Only the presentation tile is ever touched. The participant grid, your own self-view thumbnail, and Meet's controls are left exactly as they are, and remote viewers always see your full, unmodified screen share.

Development

git clone https://github.com/kud/webext-gmeet-unmirror.git
cd webext-gmeet-unmirror
npm install
npm run dev

npm run dev runs web-ext run --firefox=nightly, launching Firefox Nightly with the extension already loaded and reloaded on every save.

Other scripts:

npm run lint    # web-ext lint
npm run build   # bundle into web-ext-artifacts/

Requires Firefox 142.0 or later (strict_min_version), since the content scripts rely on world: "MAIN".

📚 Full documentation → webext-gmeet-unmirror/docs