Examine source code of Minimalist Focus Timer

{
  "manifest_version": 2,
  "name": "Pomodoro Focus Timer",
  "description": "A Minimalist Pomodoro Timer",
  "version": "0.9.2",
  "background": {
    "page": "html/background.html"
  },
  "permissions": [
    "storage",
    "notifications"
  ],
  "icons": {
    "32": "assets/icons/32.png",
    "48": "assets/icons/48.png",
    "96": "assets/icons/96.png",
    "128": "assets/icons/128.png"
  },
  "browser_action": {
    "default_popup": "html/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e2f7e529-00fb-4131-b010-db0c85c225b6}"
    }
  }
}