Examine source code of AntiProc

{
  "manifest_version": 2,
  "version": "0.4",
  "description": "An extension for maintaining your productivity by blocking sites",
  "name": "AntiProc",
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_action": {
    "default_title": "AntiProc"
  },
  "background": {
    "scripts": [
      "background_script.js"
    ]
  },
  "permissions": [
    "storage",
    "tabs",
    "webNavigation"
  ],
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
  "icons": {
    "16": "imgs/antiproc16x16.png",
    "48": "imgs/antiproc48x48.png",
    "64": "imgs/antiproc64x64.png",
    "128": "imgs/antiproc.png"
  }
}