Blowhorn Download

Install the Chrome extension

Add the Blowhorn extension from the Chrome Web Store, or load it unpacked during early access.

Install the Chrome extension

Blowhorn drives Chrome through its Chrome extension. Chrome keeps an extension inside each Chrome profile, and the extension drives only the profile it is installed in. Install it in every Chrome profile you post from.

Early access: the Chrome Web Store listing is awaiting review. Until it is approved, load the extension unpacked as described below.

From the Chrome Web Store

Open the Blowhorn listing (item fcflpiagmpcfifgknledeknedfopnapf) in each Chrome profile you post from and choose Add to Chrome. Then confirm the extension answers:

blowhorn chrome extension-status

An answered hello means the extension is loaded in some Chrome profile and talking. It does not name which profile.

Load it unpacked in one Chrome profile

When only one Chrome profile needs the extension, write the native host and follow the printed steps. Through the Blowhorn mapping:

blowhorn chrome extension-install --profile kate

By the Chrome profile directory, as blowhorn chrome profiles prints it:

blowhorn chrome extension-install --chrome-profile 'Profile 12'

--chrome-profile can be given more than once. Either flag with --all-profiles is refused. A --profile inherited from BLOWHORN_PROFILE or defaults.profile does not count: type it on this command.

The printed steps are: switch to that Chrome profile, open chrome://extensions, turn on Developer mode, choose Load unpacked, select the extension/ directory the command names, then check with blowhorn chrome extension-status. There is no file the command can write that installs an extension in one profile only, so this route always ends with those clicks.

See the files first, and write nothing:

blowhorn chrome extension-install --profile kate --dry-run

Every Chrome profile on this machine

Every profile (the default) writes Chrome's ExtensionInstallForcelist. Chrome installs the extension the next time each profile starts, with no click in that profile. That is every Chrome profile on this machine, including ones no Blowhorn profile uses. Chrome shows Managed by your organization. macOS asks for an administrator password once. Cancelling that dialog writes nothing.

blowhorn chrome extension-install --all-profiles

Ask in each profile writes Chrome's external-extensions file instead, so Chrome offers the install in each profile and you click once there. There is no managed banner.

blowhorn chrome extension-install --all-profiles --external

On Linux both files live where only root can write. Blowhorn never asks for root and refuses to run under sudo: a write it cannot make is refused with the file, its exact content, and the one sudo command that writes that file. Write that file, then run the plain install as yourself for the host.

See which route is on disk

blowhorn chrome extension-status

The report includes Install route: policy, external, or none. A policy line ends not confirmed in chrome; an external line ends waiting for your click. Those lines say what Chrome was asked to do, never that a profile's copy was confirmed.

From the desktop app

Settings has one chrome extension card. The segmented control is the route: every profile or ask in each profile. The button stays install chrome extension either way. After the command, the card lists one row per Chrome profile with the same words the terminal prints.

Move an install made before the extension id changed

Installs made before the current store item used the retired id alogghnpabnbkmhgeceffnlcbcnlpoap, which has no store listing. After you update, the native host accepts only the new id, so an extension still running under the old id cannot connect until you move it:

  1. Run the install again with the flags you used the first time.
  2. In each Chrome profile that loaded the extension unpacked, open chrome://extensions, remove the old copy, and choose Load unpacked again with the extension/ directory.
  3. If you used --all-profiles, remove the old id's entry by hand: the command adds and removes only the current id.
  4. Check with blowhorn chrome extension-status.

Your profile mappings (blowhorn chrome map) do not name the extension id and do not change.

Remove the host from before the rename

A plain install keeps com.outbox.chrome_extension.json when it is present, and names it: a Chrome profile still running the old extension connects through it. Load the Blowhorn extension in that profile, then remove the old host with:

blowhorn chrome extension-install --remove-legacy

That flag warns that a profile still on the old extension loses its connection until the Blowhorn extension is loaded there.

Last modified October 9, 2026: docs: sync from master (5f4e718)