Examine source code of CSS/JS Inject

{
  "manifest_version": 2,
  "name": "CSS/JS Inject",
  "description": "Inject your custom CSS/JS to any page. ",
  "version": "0.1.1",
  "permissions": [
    "tabs",
    "storage",
    "<all_urls>"
  ],
  "icons": {
    "64": "icons/icon.png"
  },
  "background": {
    "scripts": [
      "background_script.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "browser_action": {
    "default_icon": {
      "64": "icons/icon.png"
    },
    "default_popup": "browserAction/index.html",
    "default_title": "CSS/JS Inject"
  },
  "page_action": {
    "default_icon": {
      "64": "icons/icon.png"
    },
    "default_popup": "pageAction/index.html",
    "default_title": "CSS/JS Inject"
  },
  "options_ui": {
    "page": "options/index.html"
  },
  "web_accessible_resources": [
    "*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ae10206c-e585-4a3b-b069-a664a8e19e43}"
    }
  }
}