Examine source code of Quick Dictionary Lookup

{
  "manifest_version": 2,
  "name": "Quick Dictionary Lookup",
  "version": "1.0",
  "description": "Quickly look up the meaning of selected text.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{fd7b82f0-46ad-47bb-a980-8ccbcdec729b}"
    }
  }
}