Examine source code of PawBlock

{
  "manifest_version": 2,
  "name": "PawBlock",
  "version": "0.5.1",
  "description": "Block websites to prevent procrastination and excessive web surfing.",
  "applications": {
    "gecko": {
      "id": "@pawblock"
    }
  },
  "icons": {
    "16": "images/icon-16-on.png",
    "32": "images/icon-32-on.png",
    "48": "images/icon-48-on.png",
    "128": "images/icon-128-on.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "images/icon-16-on.png",
      "32": "images/icon-32-on.png",
      "48": "images/icon-48-on.png",
      "128": "images/icon-128-on.png"
    },
    "default_title": "PawBlock",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "scripts/background.js"
    ],
    "persistent": false
  },
  "options_page": "options.html",
  "options_ui": {
    "page": "options.html",
    "browser_style": false,
    "chrome_style": false,
    "open_in_tab": true
  },
  "permissions": [
    "https://*/*",
    "http://*/*",
    "downloads",
    "storage",
    "webNavigation"
  ],
  "web_accessible_resources": [
    "block.html"
  ]
}