Examine source code of Good Block

{
  "manifest_version": 2,
  "version": "1.0.3",
  "name": "__MSG_appName__",
  "short_name": "__MSG_appShortName__",
  "description": "__MSG_appDesc__",
  "default_locale": "en",
  "options_ui": {
    "page": "options.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "16": "assets/img/logo16.png",
    "48": "assets/img/logo48.png",
    "128": "assets/img/logo128.png"
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'; connect-src ws://localhost:*/",
  "web_accessible_resources": [
    "assets/img/*"
  ]
}