Examine source code of Playback Speed Extension

{
  "manifest_version": 3,
  "name": "Playback Speed",
  "version": "1.0.0",
  "description": "Control playback speed for all media (video/audio) with a simple, customizable interface.",
  "browser_specific_settings": {
    "gecko": {
      "id": "playback-speed@toma9411.gmail.com",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "commands": {
    "increase-speed": {
      "suggested_key": {
        "default": "Ctrl+Shift+Up",
        "mac": "Command+Shift+Up"
      },
      "description": "Increase playback speed"
    },
    "decrease-speed": {
      "suggested_key": {
        "default": "Ctrl+Shift+Down",
        "mac": "Command+Shift+Down"
      },
      "description": "Decrease playback speed"
    }
  },
  "permissions": [
    "storage",
    "activeTab",
    "tabs"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "constants-background.js",
      "storage-helpers-background.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "browser-polyfill.js",
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-48.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "options_ui": {
    "page": "settings/settings.html",
    "open_in_tab": true
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  }
}