Examine source code of Twitch-Chat-Bottom

{
  "description": "When the sceen is small Twitch chat is anchored at the bottom of the page",
  "manifest_version": 2,
  "name": "Twitch-Chat-Bottom",
  "version": "1.0.2resigned1",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "page_action": {
    "default_icon": "icons/message.svg",
    "browser_style": true,
    "default_title": "Twitch Chat Bottom"
  },
  "permissions": [
    "*://*.twitch.tv/*",
    "activeTab",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{6c46bbf0-27de-48b6-a387-eae9e06b4bfc}"
    }
  }
}