Examine source code of Turn Off the Lights for Firefox

{
  "manifest_version": 3,
  "author": "Stefan vd",
  "homepage_url": "https://www.turnoffthelights.com/support/",
  "icons": {
    "16": "images/icon16.png",
    "24": "images/icon24.png",
    "32": "images/icon32.png",
    "48": "images/icon48.png",
    "96": "images/icon96.png",
    "128": "images/icon128.png"
  },
  "default_locale": "en",
  "content_security_policy": {
    "extension_pages": "default-src 'none'; style-src 'self'; media-src https://www.turnoffthelights.com; frame-src https://www.youtube.com https://www.turnoffthelights.com; connect-src https://www.turnoffthelights.com; script-src 'self'; img-src 'self' https://www.turnoffthelights.com * data:; object-src 'none'"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "scripts/constants.js",
        "scripts/content.js",
        "scripts/eco.js"
      ],
      "run_at": "document_end"
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "styles/light.css"
      ],
      "run_at": "document_end",
      "all_frames": true,
      "match_about_blank": true
    },
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "css": [
        "styles/youtube.css"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "version": "4.6.6",
  "name": "__MSG_name__",
  "description": "__MSG_description__",
  "omnibox": {
    "keyword": "totl"
  },
  "action": {
    "default_title": "__MSG_pageatitle__",
    "default_icon": {
      "19": "images/iconstick19.png",
      "38": "images/iconstick38.png"
    }
  },
  "background": {
    "scripts": [
      "scripts/constants.js",
      "scripts/background.js"
    ]
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+L",
        "mac": "MacCtrl+Shift+L"
      }
    },
    "toggle-feature-nightmode": {
      "suggested_key": {
        "default": "Ctrl+Shift+N",
        "mac": "MacCtrl+Shift+N"
      },
      "description": "__MSG_titelnighttheme__"
    }
  },
  "web_accessible_resources": [
    {
      "resources": [
        "scripts/fps-block.js",
        "scripts/hd-quality.js"
      ],
      "matches": [
        "*://www.youtube.com/*"
      ]
    },
    {
      "resources": [
        "scripts/video-player-status.js"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "permissions": [
    "contextMenus",
    "tabs",
    "storage",
    "webNavigation",
    "scripting",
    "theme"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "stefanvandamme@stefanvd.net",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {}
  },
  "host_permissions": [
    "<all_urls>"
  ]
}