Examine source code of E-SIGN

{
  "manifest_version": 2,
  "name": "__MSG_appName__",
  "short_name": "__MSG_appShortName__",
  "description": "__MSG_appDescription__",
  "default_locale": "en",
  "version": "1.6.1",
  "author": "Asseco Lietuva, UAB <info@asseco.lt>",
  "icons": {
    "16": "icons/esign-16.png",
    "32": "icons/esign-32.png",
    "48": "icons/esign-48.png",
    "128": "icons/esign-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "*://*/*"
      ],
      "all_frames": true
    }
  ],
  "permissions": [
    "nativeMessaging",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "58.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{3dd964e7-f4a2-4101-a166-6b132172fdd4}"
    }
  }
}