Examine source code of Twitch Alerter

{
  "manifest_version": 2,
  "name": "Twitch Tracker",
  "version": "1.0",
  "description": "A program to track when certain Twitch streamers are online.",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_title": "Twitch Tracker",
    "default_popup": "index.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "main.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "main.js"
    ]
  },
  "permissions": [
    "tabs",
    "webRequest",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3dbc97d1-6980-438e-914a-79963592ecf5}",
      "strict_min_version": "57.0"
    }
  }
}