Examine source code of Cambridge Dictionary

{
  "name": "Cambridge Dictionary",
  "description": "The Firefox version of Cambridge Dictionary Lookup extension",
  "version": "0.1.1",
  "homepage_url": "https://github.com/fabiobarkoski/cambridge-dictionary-addon",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "index.html",
    "default_title": "Cambridge Dictionary",
    "default_icon": "cd-logo.png"
  },
  "icons": {
    "48": "cd-logo.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{28308405-b866-4416-b86b-3568389e0dbf}"
    }
  }
}