Examine source code of Cache Me If You Can

{
  "manifest_version": 2,
  "name": "Cache Me If You Can",
  "short_name": "Cache Images",
  "version": "1.1.5",
  "description": "Capture les images reçues par Firefox dans un onglet, même si le site les retire ensuite.",
  "developer": {
    "name": "ECLS Studio",
    "url": "https://ecls.me/projects/cache-me-if-you-can"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "cache-me-if-you-can@ecls.me",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "page": "background.html",
    "persistent": true
  },
  "browser_action": {
    "default_title": "Cache Me If You Can",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "19": "icons/icon-19.png",
      "32": "icons/icon-32.png",
      "38": "icons/icon-38.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "http://*/*",
    "https://*/*",
    "webRequest",
    "webRequestBlocking",
    "unlimitedStorage"
  ],
  "incognito": "spanning",
  "content_security_policy": "script-src 'self'; object-src 'none'; img-src 'self' blob: data:"
}