Examine source code of External Playlist for YouTube

{
  "manifest_version": 2,
  "name": "External Playlist for YouTube",
  "version": "2.0.3",
  "description": "Compress the open YouTube tabs in the current window into a single queue tab.",
  "browser_specific_settings": {
    "gecko": {
      "id": "external-playlist@orbital-q",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "16": "extension/icons/icon16.png",
    "32": "extension/icons/icon32.png",
    "48": "extension/icons/icon48.png",
    "64": "extension/icons/icon64.png",
    "128": "extension/icons/icon128.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "bookmarks"
  ],
  "sidebar_action": {
    "default_panel": "extension/sidepanel.html",
    "default_title": "xPlaylist",
    "default_icon": {
      "16": "extension/icons/icon16.png",
      "32": "extension/icons/icon32.png",
      "48": "extension/icons/icon48.png"
    }
  },
  "background": {
    "scripts": [
      "extension/background/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/watch*"
      ],
      "js": [
        "extension/content/page-world/suppress-autoplay.js",
        "extension/content/page-world/media-keys.js"
      ],
      "run_at": "document_start",
      "world": "MAIN"
    },
    {
      "matches": [
        "*://www.youtube.com/watch*"
      ],
      "js": [
        "extension/content/autoadvance.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_action": {
    "default_title": "Stash YouTube tabs into the external playlist",
    "default_icon": {
      "19": "extension/icons/icon19.png",
      "38": "extension/icons/icon38.png",
      "48": "extension/icons/icon48.png"
    },
    "theme_icons": [
      {
        "light": "extension/icons/icon16.png",
        "dark": "extension/icons/icon16-light.png",
        "size": 16
      },
      {
        "light": "extension/icons/icon19.png",
        "dark": "extension/icons/icon19-light.png",
        "size": 19
      },
      {
        "light": "extension/icons/icon32.png",
        "dark": "extension/icons/icon32-light.png",
        "size": 32
      },
      {
        "light": "extension/icons/icon38.png",
        "dark": "extension/icons/icon38-light.png",
        "size": 38
      },
      {
        "light": "extension/icons/icon48.png",
        "dark": "extension/icons/icon48-light.png",
        "size": 48
      }
    ]
  }
}