Examine source code of YouTube Popout Player

{
  "manifest_version": 3,
  "name": "__MSG_ExtensionName__",
  "description": "__MSG_ExtensionDescription__",
  "version": "5.2.2",
  "short_name": "__MSG_ExtensionShortName__",
  "icons": {
    "16": "icons/16.png",
    "19": "icons/19.png",
    "24": "icons/24.png",
    "32": "icons/32.png",
    "38": "icons/38.png",
    "48": "icons/48.png",
    "64": "icons/64.png",
    "96": "icons/96.png",
    "128": "icons/128.png"
  },
  "default_locale": "en",
  "homepage_url": "https://rthaut.github.io/YouTubePopoutPlayer/",
  "developer": {
    "name": "Ryan Thaut",
    "url": "https://ryan.thaut.me"
  },
  "action": {
    "default_title": "__MSG_BrowserActionTitle__"
  },
  "commands": {
    "open-popout-auto-close-command": {
      "suggested_key": {
        "default": "Ctrl+Up"
      },
      "description": "__MSG_OpenPopoutCommandDescription__"
    },
    "open-popout-force-close-command": {
      "description": "__MSG_OpenPopoutForceCloseCommandDescription__",
      "suggested_key": {
        "default": "Alt+Shift+PageUp"
      }
    },
    "open-popout-no-close-command": {
      "description": "__MSG_OpenPopoutNoCloseCommandDescription__",
      "suggested_key": {
        "default": "Alt+Shift+PageDown"
      }
    },
    "rotate-video-left": {
      "suggested_key": {
        "default": "Alt+Shift+A"
      },
      "description": "__MSG_RotateVideoLeftCommandDescription__"
    },
    "rotate-video-right": {
      "suggested_key": {
        "default": "Alt+Shift+D"
      },
      "description": "__MSG_RotateVideoRightCommandDescription__"
    }
  },
  "declarative_net_request": {
    "rule_resources": [
      {
        "id": "rules",
        "enabled": true,
        "path": "rules.json"
      }
    ]
  },
  "host_permissions": [
    "*://*.youtube.com/*",
    "*://*.youtube-nocookie.com/*"
  ],
  "permissions": [
    "contextMenus",
    "declarativeNetRequest",
    "notifications",
    "storage"
  ],
  "optional_permissions": [
    "tabs",
    "cookies"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{85b42b8f-49cd-4935-aeca-a6b32dd6ac9f}",
      "strict_min_version": "113.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "open_in_tab": false,
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube-nocookie.com/*",
        "*://*.youtube.com/*"
      ],
      "all_frames": true,
      "run_at": "document_end",
      "css": [
        "content-scripts/content.css"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}