Examine source code of Unsplash Image Search

{
  "manifest_version": 2,
  "name": "Unsplash Image Search",
  "description": "A simple browser widget to search for images on Unsplash using a query and return a list of image elements with thumbnails that let you copy the photo url on Unsplash.",
  "version": "1.2",
  "browser_action": {
    "default_popup": "index.html"
  },
  "permissions": [],
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{9ebc2fa9-7ff1-4452-bde0-2c8cb2e40956}"
    }
  }
}