Examine source code of DictMemo

{
  "manifest_version": 2,
  "name": "DictMemo",
  "version": "1.2.0",
  "description": "A Firefox extension to help memorize new words by looking up definitions in dictionaries while browsing",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "dictmemo@firefox.com"
    }
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "storage",
    "tabs",
    "https://www.larousse.fr/*",
    "https://dictionary.cambridge.org/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "DictMemo",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    }
  },
  "web_accessible_resources": [
    "popup.html",
    "dictionary.html",
    "review.html"
  ]
}