Examine source code of Focus Lock

{
  "manifest_version": 2,
  "name": "Focus Lock",
  "version": "2.0",
  "description": "Focus Lock helps you stay focused by blocking distracting sites during focus time.",
  "permissions": [
    "storage",
    "webRequest",
    "webRequestBlocking",
    "*://*/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup/popup.html",
    "default_icon": "icons/icon-128.png"
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{014495e4-eef1-4b7d-9702-123034efad4c}"
    }
  }
}