Examine source code of Image Block X

{
  "description": "Add a button to the toolbar to disable loading all images",
  "manifest_version": 2,
  "name": "Image Block X",
  "version": "0.6resigned1",
  "homepage_url": "https://github.com/ckuhl/ImageBlockX/",
  "icons": {
    "16": "icons/image_blocked.svg",
    "24": "icons/image_blocked.svg",
    "32": "icons/image_blocked.svg",
    "48": "icons/image_blocked.svg",
    "64": "icons/image_blocked.svg",
    "128": "icons/image_blocked.svg",
    "256": "icons/image_blocked.svg",
    "512": "icons/image_blocked.svg"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "storage"
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/image_allowed.svg",
    "default_title": "Images are allowed"
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0035bf10-3f36-4d60-b92d-08c1a8b060a6}"
    }
  }
}