Examine source code of Open Dictionary

{
  "manifest_version": 2,
  "name": "Open Dictionary",
  "browser_specific_settings": {
    "gecko": {
      "id": "kodeshape@open-dictionary",
      "strict_min_version": "112.0"
    }
  },
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "icons/Icon.png"
  },
  "icons": {
    "48": "icons/Icon.png",
    "96": "icons/Icon@2x.png",
    "144": "icons/Icon@3x.png"
  },
  "options_ui": {
    "page": "options.html"
  },
  "background": {
    "scripts": [
      "assets/background.js"
    ],
    "type": "module"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*/*"
      ],
      "js": [
        "assets/browser-polyfill.min.js",
        "assets/content_script.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "assets/*.js"
  ],
  "permissions": [
    "storage",
    "history",
    "tabs",
    "scripting"
  ],
  "description": "Open dictionary using shortcuts for any word highlighted in languages you want from list of web dictionary that you set",
  "version": "1.0.1"
}