Examine source code of ToggleViewer

{
  "description": "Allows you to switch on/off the twitch viewer count",
  "manifest_version": 2,
  "name": "ToggleViewer",
  "version": "1.0.0.3",
  "homepage_url": "https://github.com/akaJuliaan",
  "icons": {
    "48": "icons/IconW.svg",
    "96": "icons/IconW.svg",
    "128": "icons/IconW.svg"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "*://*.twitch.tv/*"
  ],
  "browser_action": {
    "default_icon": "icons/IconW.svg",
    "theme_icons": [
      {
        "light": "icons/IconW.svg",
        "dark": "icons/IconB.svg",
        "size": 32
      }
    ],
    "default_title": "ToggleViewer"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{782593f5-57b7-491c-b550-b325f3024fff}"
    }
  }
}