Examine source code of Ha Invoice

{
  "manifest_version": 2,
  "name": "Ha Invoice",
  "version": "0.0.1",
  "description": "Expose HaApi to web apps with confirmation",
  "browser_specific_settings": {
    "gecko": {
      "id": "careerofhammim@gmail.com"
    }
  },
  "icons": {
    "48": "icons/logo-48-square.png",
    "128": "icons/icon.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "action": {
    "default_title": "HA Invoice"
  },
  "web_accessible_resources": [
    "inject.js"
  ]
}