Examine source code of Upvote Anywhere

{
  "name": "Upvote Anywhere - Reddit comments on YouTube",
  "short_name": "Upvote Anywhere",
  "description": "View Reddit comments on YouTube or any webpage.",
  "version": "2.2.5",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "storage",
    "tabs",
    "*://*.reddit.com/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/logo_16.png",
      "32": "images/logo_32.png",
      "48": "images/logo_48.png",
      "128": "images/logo_128.png"
    }
  },
  "icons": {
    "16": "images/logo_16.png",
    "32": "images/logo_32.png",
    "48": "images/logo_48.png",
    "128": "images/logo_128.png"
  },
  "web_accessible_resources": [
    "images/youtube_32.png",
    "images/reddit_32.png"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "redditWherever@example.com"
    }
  }
}