Examine source code of unsocial

{
  "name": "__MSG_appName__",
  "description": "__MSG_appDescription__",
  "version": "1.1resigned1",
  "manifest_version": 2,
  "default_locale": "en",
  "icons": {
    "16": "images/icon-16.png",
    "128": "images/icon-128.png"
  },
  "options_ui": {
    "page": "pages/options.html",
    "browser_style": true
  },
  "applications": {
    "gecko": {
      "id": "unsocial@timschoch.com",
      "strict_min_version": "42.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://medium.com/*"
      ],
      "js": [
        "scripts/unsocial-medium.js"
      ],
      "css": [
        "styles/unsocial-medium.css"
      ],
      "run_at": "document_end",
      "all_frames": false
    }
  ],
  "permissions": [
    "storage"
  ]
}