Examine source code of Tab Volume Control

{
  "manifest_version": 3,
  "name": "Tab Volume Control",
  "version": "2.4.0",
  "description": "Control volume for individual browser tabs from 0% to 500%. I originally created this for my personal use after being tired of looking through shady add-ons with overreaching permissions.",
  "permissions": [
    "activeTab",
    "storage",
    "tabs",
    "theme"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_icon": {
      "16": "src/icons/icon16.svg",
      "48": "src/icons/icon48.svg",
      "128": "src/icons/icon128.svg"
    },
    "default_title": "Tab Volume Control",
    "default_popup": "src/ui/popup.html"
  },
  "background": {
    "scripts": [
      "src/background/tabManager.js",
      "src/background/background.js"
    ]
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Alt+Shift+V"
      },
      "description": "Open the volume control popup"
    },
    "volume-up": {
      "suggested_key": {
        "default": "Alt+Shift+Up"
      },
      "description": "Increase volume of the current tab"
    },
    "volume-down": {
      "suggested_key": {
        "default": "Alt+Shift+Down"
      },
      "description": "Decrease volume of the current tab"
    },
    "toggle-mute": {
      "suggested_key": {
        "default": "Alt+Shift+M"
      },
      "description": "Mute / unmute the current tab"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "js": [
        "src/content/modules/constants.js",
        "src/content/modules/audioManager.js",
        "src/content/modules/volumeController.js",
        "src/content/modules/mediaElementRegistry.js",
        "src/content/modules/mediaScanner.js",
        "src/content/content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "src/icons/icon16.svg",
    "48": "src/icons/icon48.svg",
    "128": "src/icons/icon128.svg"
  },
  "author": "Sebastian Engvall",
  "homepage_url": "https://github.com/seen91/FireFoxTabVolumeControl",
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-volume-control@sebastianengvall.github.io",
      "strict_min_version": "115.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}