Examine source code of Holy SEO!

{
  "manifest_version": 3,
  "name": "__MSG_extName__",
  "version": "2.2.1",
  "description": "__MSG_extDescription__",
  "default_locale": "pl",
  "author": "Damian Smilgin",
  "permissions": [
    "activeTab",
    "scripting",
    "webRequest",
    "clipboardWrite",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_area": "navbar",
    "default_title": "__MSG_extName__",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "background": {
    "scripts": [
      "js/core-utils.js",
      "js/background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "holy-seo@damian-smilgin",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "commands": {
    "count-chars": {
      "suggested_key": {
        "default": "Alt+C"
      },
      "description": "__MSG_cmdChars__"
    },
    "show-headings": {
      "suggested_key": {
        "default": "Alt+H"
      },
      "description": "__MSG_cmdHeadings__"
    },
    "show-alts": {
      "suggested_key": {
        "default": "Alt+A"
      },
      "description": "__MSG_cmdAlts__"
    },
    "show-missing-alts": {
      "suggested_key": {
        "default": "Alt+Shift+A"
      },
      "description": "__MSG_cmdNoAlts__"
    },
    "link-grabber": {
      "suggested_key": {
        "default": "Alt+L"
      },
      "description": "__MSG_cmdLinks__"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/keyword-extractor.js",
        "js/content.js"
      ],
      "css": [
        "css/content.css"
      ],
      "run_at": "document_idle"
    }
  ]
}