Examine source code of Bluhell Firewall

{
  "name": "Bluhell Firewall",
  "description": "Lightweight Ad-Blocker and Tracking/Privacy Protector.",
  "homepage_url": "https://github.com/diegocr",
  "author": "Diego Casorran",
  "version": "2.9",
  "manifest_version": 2,
  "applications": {
    "gecko": {
      "id": "{6BB5760D-F97E-421B-AF5B-8457A90C3CED}",
      "strict_min_version": "57.0"
    }
  },
  "permissions": [
    "<all_urls>",
    "webRequest",
    "webRequestBlocking"
  ],
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "64": "icon.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icon16.png",
      "19": "icon16.png",
      "32": "icon32.png",
      "38": "icon32.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "web_accessible_resources": [
    "icon.png",
    "blocked.js",
    "blocked.css",
    "blocked.xhtml"
  ]
}