Examine source code of Focus Rizz

{
  "manifest_version": 2,
  "name": "Focus Rizz",
  "version": "1.1",
  "description": "Block distracting sites and stay focused with a timer.",
  "permissions": [
    "storage",
    "tabs",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{abe190e9-5ffc-4678-9bc9-7360492d07a1}"
    }
  }
}