Examine source code of Mullvad

{
  "manifest_version": 3,
  "name": "Mullvad VPN",
  "version": "4.0.4",
  "description": "Mullvad VPN Extension – Protect your online privacy and secure your internet connections. Easily check your connection status and get quick access to Mullvad services.",
  "browser_specific_settings": {
    "gecko": {
      "id": "supportfirefox@mullvad.net",
      "strict_min_version": "91.1.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "permissions": [
    "storage",
    "alarms",
    "notifications",
    "privacy",
    "proxy",
    "webRequest",
    "webRequestBlocking"
  ],
  "host_permissions": [
    "https://ipv4.am.i.mullvad.net/*",
    "https://ipv6.am.i.mullvad.net/*",
    "https://mullvad.net/*",
    "https://*.mullvad.net/*",
    "https://mullvad.com/*",
    "https://*.mullvad.com/*",
    "https://mullvad.statuspage.io/*",
    "https://mullvad.b-cdn.net/*",
    "https://mullvad-api.net/*",
    "https://api.mullvad.net/*",
    "https://vpn.mullvad.net/*",
    "https://checkout.mullvad.net/*",
    "https://account.mullvad.net/*",
    "https://www.mullvad.net/*",
    "https://blog.mullvad.net/*",
    "https://guides.mullvad.net/*",
    "https://download.mullvad.net/*",
    "https://mullvad-dns.net/*",
    "https://dns.mullvad.net/*",
    "https://wg.mullvad.net/*",
    "https://openvpn.mullvad.net/*",
    "https://wireguard.mullvad.net/*",
    "https://socks.mullvad.net/*",
    "https://bridge.mullvad.net/*",
    "https://relay.mullvad.net/*",
    "https://server-electrum.us/*",
    "https://electrum-server.org/*",
    "https://electrum.mullvad.net/*",
    "https://electrumx.mullvad.net/*"
  ],
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "author": "Mullvad Security Team",
  "homepage_url": "https://mullvad.net"
}