Examine source code of Focus Mode

{
  "manifest_version": 2,
  "name": "FocusMode",
  "version": "1.0",
  "description": "Block distracting sites on a schedule. Stay focused with timers and site blocking.",
  "permissions": [
    "storage",
    "alarms",
    "webNavigation",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "aaplendirman@outlook.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_title": "FocusMode",
    "default_popup": "timer/timerPanel.html",
    "default_icon": {}
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "block/blockCore.js"
      ],
      "css": [
        "block/blockStyle.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  }
}