> ## Documentation Index > Fetch the complete documentation index at: https://docs.asymptotelabs.ai/llms.txt > Use this file to discover all available pages before exploring further. # Chromium Browsers > Which Chromium browsers the Asymptote browser extension is tested in, how events name the browser, and how to verify and deploy it in Edge, Brave, Opera, Vivaldi, and Arc ## Overview Microsoft Edge, Brave, Opera, Vivaldi, and Arc are all built on Chromium and all run Manifest V3 extensions. The [browser extension](https://docs.asymptotelabs.ai/runtimes/browser-extension.md) ships one build, and that same build loads in each of them. There is no per-browser port and no second artifact. A browser being Chromium-based does not mean Asymptote has tested it there. This page keeps the two claims apart: which browsers run in automated tests on every change, and which rely on the manual checklist below. ## Support levels | Browser | Status | How it is verified | | - | - | - | | Chromium | Tested | Automated replay e2e in CI on every pull request (`BROWSER_CHANNEL=chromium`) | | Microsoft Edge | Tested | Automated replay e2e in CI on every pull request (`BROWSER_CHANNEL=msedge`) | | Google Chrome | Expected to work, not in CI | Branded Chrome (137 and later) no longer honors `--load-extension`, which the harness uses to load `dist/`, so it cannot run in the automated e2e. Use the [manual checklist](#manual-verification-checklist) | | Brave | Expected to work, not in CI | [Manual checklist](#manual-verification-checklist). There is no Playwright channel for Brave | | Opera, Opera GX | Expected to work, not in CI | [Manual checklist](#manual-verification-checklist). There is no Playwright channel for Opera | | Vivaldi | Expected to work, not in CI | [Manual checklist](#manual-verification-checklist). There is no Playwright channel for Vivaldi | | Arc | Expected to work, not in CI | [Manual checklist](#manual-verification-checklist). There is no Playwright channel for Arc, and Arc does not run on Linux CI runners | | Firefox | Beta, separate build | Not Chromium: a separate `dist-firefox` build, linted in CI; live capture still requires manual verification. See [Load it in Firefox](https://docs.asymptotelabs.ai/runtimes/browser-extension.md#load-it-in-firefox) | | Safari | Not supported | Experimental build and packaging scaffolding exists, but it has not been tested in Safari and is not shipped | The extension needs a browser built on Chromium 111 or newer, because its interceptor is declared as a main-world content script in the manifest. ## Which browser an event came from Every event the extension sends names the browser that produced it. On a managed fleet that matters: a paste into ChatGPT from the managed Edge profile and one from a personal Brave install are different investigations. The extension's service worker reads the browser's own UA Client Hints brand list (`navigator.userAgentData.brands`), falling back to the user-agent string, and sends OpenTelemetry semantic-convention attributes on every OTLP log: | OTLP attribute | Example | Where it lands in the event | | - | - | - | | `user_agent.name` | `Microsoft Edge` | `user_agent.name` | | `user_agent.version` | `153` (major version) | `user_agent.version` | | `browser.brands` | `["Microsoft Edge 153", "Not_A Brand 8", "Chromium 153"]` | `raw.attributes` | | `user_agent.original` | the browser's UA string | `raw.attributes` | `user_agent.name` and `user_agent.version` are typed event fields. They are metadata rather than content, so they survive every retention mode, including `metadata` retention in the extension and Metadata-only managed forwarding, which drops `raw`. Threat rules can match on `e.user_agent.name`. To see the browser on recent events: ```bash theme={null} grep '"claude_web"\|"chatgpt_web"' ~/.beacon/endpoint/logs/runtime.jsonl | tail -5 | jq '{harness: .harness.name, browser: .user_agent.name, version: .user_agent.version}' ``` `user_agent.name` is what the browser claims to be. Some browsers do not name themselves: | Browser | Reports as | Why | | - | - | - | | Microsoft Edge | `Microsoft Edge` | Edge adds its own brand | | Brave | `Brave` | Brave adds its own brand. Builds that do not are still recognized by Brave's `navigator.brave` object | | Opera, Opera GX | `Opera`, `Opera GX` | Opera adds its own brand. `user_agent.version` is Opera's version, not Chromium's | | Google Chrome | `Google Chrome` | | | Chromium, and Playwright's test build | `Chromium` | No vendor brand | | Vivaldi | Usually `Chromium` | Vivaldi adds no brand of its own and copies Chrome's UA string for site compatibility. Older builds that still put `Vivaldi/` in the UA string without brand hints report `Vivaldi` | | Arc | Usually `Google Chrome` | Arc copies Chrome's brand list and UA string. An extension's service worker has no other signal, so Arc cannot be told apart from Chrome | | Firefox | `Firefox` | Firefox has no UA Client Hints, so the name and major version come from the `Firefox/` token in its UA string, and `browser.brands` is omitted | When a browser adds a brand Asymptote does not know, that brand is reported as-is. When a browser gives neither brand hints nor a recognizable UA string, the attributes are omitted rather than guessed. ## Install Every Chromium browser uses the same archive, `agent-beacon-browser-extension--chrome.zip`, or a local `dist/` build. The `-chrome` suffix names the Chromium extension family, not Google Chrome alone; the Firefox build ships separately as `-firefox.xpi`. See [Use a release archive](https://docs.asymptotelabs.ai/runtimes/browser-extension.md#use-a-release-archive) for download and verification. Load it unpacked from the browser's extensions page, with developer mode turned on: | Browser | Extensions page | Developer mode toggle | | - | - | - | | Google Chrome, Chromium | `chrome://extensions` | Top right | | Microsoft Edge | `edge://extensions` | Left sidebar | | Brave | `brave://extensions` | Top right | | Opera, Opera GX | `opera://extensions` | Top right | | Vivaldi | `vivaldi://extensions` | Top right | | Arc | `chrome://extensions` | Top right | Then choose **Load unpacked** and select the `dist` folder or the unzipped release folder, as described in [Load it in Chrome](https://docs.asymptotelabs.ai/runtimes/browser-extension.md#load-it-in-chrome). The extension is not published in any extension store yet. When it is, Brave, Vivaldi, and Arc install from the Chrome Web Store, Opera needs its own add-ons listing (or the user allows Chrome Web Store installs in Opera), and Edge needs its own Microsoft Edge Add-ons listing through Partner Center. No Edge Add-ons submission exists today. ## Manual verification checklist Use this for every browser the automated e2e does not cover, and record the result. Two passes: the replay e2e, which needs no login and no network, and a live check against the real sites. ### 1. Replay e2e against the browser binary The Playwright harness accepts any Chromium-family binary through `BROWSER_EXECUTABLE`. It launches the browser with the built extension and replays recorded chat streams through it, which proves the extension loads, the interceptor fires, and delivery works in that browser. ```bash theme={null} cd browser-extension npm ci npm run build BROWSER_EXECUTABLE="/Applications/Brave Browser.app/Contents/MacOS/Brave Browser" npx playwright test ``` Typical executable paths: | Browser | macOS | Linux | | - | - | - | | Brave | `/Applications/Brave Browser.app/Contents/MacOS/Brave Browser` | `/usr/bin/brave-browser` | | Opera | `/Applications/Opera.app/Contents/MacOS/Opera` | `/usr/bin/opera` | | Vivaldi | `/Applications/Vivaldi.app/Contents/MacOS/Vivaldi` | `/usr/bin/vivaldi` | | Arc | `/Applications/Arc.app/Contents/MacOS/Arc` | Not available | On Windows, the path is the **Target** of the browser's shortcut (right-click the shortcut, then **Properties**). `BROWSER_CHANNEL` selects a Playwright channel instead (`chromium`, the default, or `msedge`; pre-release variants such as `msedge-beta` also work). `BROWSER_EXECUTABLE` wins when both are set. A browser that ignores `--load-extension`, as branded Chrome does, fails every test at the first step, which is itself a useful result: skip to the live check. ### 2. Live check against the real sites With the Asymptote endpoint running: * [ ] Load the extension unpacked from the browser's extensions page. It appears in the list, is enabled, and shows no errors. * [ ] The toolbar popup opens and shows capture on and a queue depth of 0. * [ ] Send one message on claude.ai. A `claude_web` event arrives in the runtime log. * [ ] Send one message on chatgpt.com. A `chatgpt_web` event arrives in the runtime log. * [ ] Both events carry `user_agent.name`. Note the value; see [Which browser an event came from](#which-browser-an-event-came-from) for what each browser should report. * [ ] No permission prompt about local network access appeared. The service worker console, from the extensions page, shows no delivery errors. * [ ] Quit and restart the browser. The extension is still enabled and the next message is still captured. * [ ] Browser-specific: in Brave, repeat one message with Shields up for the site; in Opera, confirm the extension is allowed on claude.ai and chatgpt.com; in Arc, check whether capture also works in a Space that uses a different profile, and record the answer. ### 3. Record the result Add a row to the pull request or release notes that ran it: | Browser | Version | OS | Date | Replay e2e | Live check | `user_agent.name` seen | | - | - | - | - | - | - | - | | *e.g. Brave* | *1.x (Chromium N)* | *macOS 15* | *YYYY-MM-DD* | *pass/fail* | *pass/fail* | *Brave* | ## Force-install through browser policy For IT-managed fleets, Chromium browsers can install an extension without user action through the `ExtensionInstallForcelist` policy, or its successor `ExtensionSettings` with `installation_mode: force_installed`. Each browser reads that policy from its own location: | Browser | Windows registry key | macOS preference domain | Linux policy directory | | - | - | - | - | | Google Chrome | `HKLM\SOFTWARE\Policies\Google\Chrome` | `com.google.Chrome` | `/etc/opt/chrome/policies/managed/` | | Microsoft Edge | `HKLM\SOFTWARE\Policies\Microsoft\Edge` (Edge ADMX) | `com.microsoft.Edge` | `/etc/opt/edge/policies/managed/` | | Brave | `HKLM\SOFTWARE\Policies\BraveSoftware\Brave` (Brave ADMX) | `com.brave.Browser` | `/etc/brave/policies/managed/` | | Chromium | `HKLM\SOFTWARE\Policies\Chromium` | `org.chromium.Chromium` | `/etc/chromium/policies/managed/` | | Opera, Vivaldi, Arc | Not verified | Not verified | Not verified | Asymptote has not verified an enterprise policy path for Opera, Vivaldi, or Arc. Check the vendor's current enterprise documentation, and test on one machine, before relying on policy there. Each `ExtensionInstallForcelist` entry is `;`. Two things block force-install today: * **There is no update URL to point at.** The extension is not in the Chrome Web Store or Microsoft Edge Add-ons, and Asymptote does not publish a signed `.crx` with an update manifest. Force-install needs one of those. * **There is no stable extension ID.** An unpacked extension's ID is derived from the folder it was loaded from, because the manifest carries no `key`. A policy has nothing fixed to name until the extension is packaged with a key or listed in a store. Until then, distribution is load-unpacked. Managed profiles can also block developer mode, which blocks **Load unpacked**. If your fleet does, allow developer mode for the profiles that should run the extension, or wait for a store listing. ## Related > **[Browser extension](https://docs.asymptotelabs.ai/runtimes/browser-extension.md)** > > Install, configuration, and troubleshooting. > **[Schema fields](https://docs.asymptotelabs.ai/telemetry-schema/fields.md)** > > Where `user_agent` sits in the event schema. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.