Examine source code of Live Slides Timer

{
  "icons": {
    "16": "icon16.plasmo.e7bcd3ac.png",
    "32": "icon32.plasmo.ce39377b.png",
    "48": "icon48.plasmo.3c17e113.png",
    "64": "icon64.plasmo.df317abe.png",
    "128": "icon128.plasmo.6a4310c5.png"
  },
  "manifest_version": 2,
  "browser_action": {
    "default_icon": {
      "16": "icon16.plasmo.e7bcd3ac.png",
      "32": "icon32.plasmo.ce39377b.png",
      "48": "icon48.plasmo.3c17e113.png",
      "64": "icon64.plasmo.df317abe.png",
      "128": "icon128.plasmo.6a4310c5.png"
    },
    "default_popup": "popup.html"
  },
  "version": "1.0.0",
  "author": "",
  "name": "Live Slides Timer",
  "description": "Add or insert a live countdown timer into your slides — visible to the audience during presentation. Works instantly.",
  "background": {
    "scripts": [
      "static/background/index.js"
    ]
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://docs.google.com/presentation*"
      ],
      "js": [
        "slides-timer.bd21e2d5.js"
      ],
      "css": []
    },
    {
      "matches": [
        "https://docs.google.com/presentation*"
      ],
      "js": [
        "builder-ui.3ca5ede5.js"
      ],
      "css": []
    }
  ],
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "slides_timer@crx.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}