Examine source code of QuietBreak

{
  "manifest_version": 2,
  "name": "QuietBreak",
  "version": "1.1.6",
  "description": "Mutes enabled Twitch tabs while an advertisement is playing, then restores their previous sound state.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{c8b7d326-b0fe-4b6b-966a-58c391e0d5d5}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "strict_min_version": "142.0"
    }
  },
  "permissions": [
    "storage",
    "tabs",
    "*://*.twitch.tv/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "QuietBreak",
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/quietbreak.svg",
      "32": "icons/quietbreak.svg"
    }
  },
  "icons": {
    "48": "icons/quietbreak.svg",
    "96": "icons/quietbreak.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.twitch.tv/*"
      ],
      "js": [
        "detector.js",
        "media-guard.js",
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}