Examine source code of FocusSurfing - Block Distracting Websites

{
  "manifest_version": 2,
  "name": "FocusSurfing - Block Distracting Websites",
  "version": "2.0.1",
  "description": "FocusSurfing is a firefox extension that you can use to help keep you focused and productive. This is done by limiting the amount of time on those pesky websites you love but spend way too much time on them.  My pesky websites are Facebook and youtube lol",
  "homepage_url": "https://focussurfing.org/",
  "icons": {
    "48": "icons/fs_icon.png"
  },
  "permissions": [
    "activeTab",
    "webNavigation",
    "tabs",
    "alarms",
    "storage",
    "unlimitedStorage"
  ],
  "browser_action": {
    "default_icon": "icons/fs_popup.png",
    "default_title": "FocusSurfing",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "common/common.js",
      "background/helper.js",
      "background/background.js"
    ],
    "persistent": true
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "js": [
        "content_scripts/activity-tracker.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3cdcfe5c-dacf-4dae-b57c-8f65166db828}"
    }
  }
}