Examine source code of jstardict

{
  "manifest_version": 3,
  "name": "jstardict",
  "version": "2.12.2",
  "browser_specific_settings": {
    "gecko": {
      "id": "jstardict@gholk.github.io"
    }
  },
  "description": "lookup stardict format dict in browser.",
  "homepage_url": "https://gitlab.com/gholk/jstardict",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "storage",
    "scripting",
    "webNavigation",
    "activeTab"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_icon": "icon.png",
    "default_title": "jstardict options",
    "default_popup": "option/index.html?mode=popup"
  },
  "options_ui": {
    "page": "option/index.html",
    "open_in_tab": false
  },
  "content_scripts": [],
  "background": {
    "scripts": [
      "common.js",
      "dist/background.js"
    ]
  },
  "web_accessible_resources": [
    {
      "resources": [
        "content.css"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}