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Manifest V3 generator

Manifest V3 downloads permission

The downloads permission enables chrome.downloads — starting a download from a URL or data URI with a chosen filename, watching its progress, and opening, pausing, resuming or erasing entries in the browser's download list.

It carries the install warning 'Manage your downloads'. If the extension only needs to save one file the user asked for, an anchor with the download attribute in the popup does the same job with no permission and no warning.

Downloads at a glance

Manifest key
"permissions": ["downloads"]
What it enables
Start downloads and watch them finish.
Install warning
"Manage your downloads"
Cross-browser API
browser.downloads via webextension-polyfill

The manifest that declares it

Manifest with this permission

manifest.json
{
  "manifest_version": 3,
  "name": "my-extension",
  "version": "0.1.0",
  "action": {
    "default_popup": "src/popup.html"
  },
  "background": {
    "service_worker": "src/background.ts",
    "type": "module"
  },
  "permissions": [
    "downloads"
  ]
}

Installing this manifest shows the warning "Manage your downloads".

downloads, answered

The longer version is in the guide Manifest V3 permissions: a practical guide.

What does the downloads permission do in Manifest V3?
Start downloads and watch them finish. It is declared as the string "downloads" in the manifest's permissions array; the browser grants it at install time, and the extension's service worker, popup and other pages can then call the matching API.
Does downloads show an install warning?
Yes. Chrome shows "Manage your downloads" before the extension installs and again if the permission is added in an update, which disables the extension until the user accepts. That sentence is the most expensive text an extension ever shows, so declare downloads only when the feature cannot be built without it.
Can I request downloads at runtime instead?
Yes. Move it from permissions to optional_permissions and call browser.permissions.request({ permissions: ["downloads"] }) from a user gesture when the feature is first used. The manifest generator emits the install-time form; optional grants are an edit to that JSON.

Build the whole manifest

The Chrome extension manifest generator declares every permission with its install warning shown up front, adds the surfaces the browser opens, and validates content-script match patterns before they can reject the whole extension. In the Nodlume workspace the same selection becomes a complete Manifest V3 project with a service worker and a Vite build.

Open the generator

Other Manifest V3 permissions

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