Examine source code of BriskNote

{
  "manifest_version": 3,
  "name": "BriskNote",
  "description": "Take notes on any new browser tab and sync them with your phone",
  "version": "0.2",
  "icons": {
    "16": "static/media/bn-icon-black-16x16-browser-manifest.png",
    "48": "static/media/bn-icon-black-48x48-browser-manifest.png",
    "128": "static/media/bn-icon-black-128x128-browser-manifest.png"
  },
  "background": {
    "scripts": [
      "static/js/lib/pouchdb.min.js",
      "background.js"
    ]
  },
  "action": {
    "default_title": "BriskNote: New Tab Notes",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "static/media/bn-icon-black-16x16-browser-manifest.png",
      "24": "static/media/bn-icon-black-24x24-browser-manifest.png",
      "32": "static/media/bn-icon-black-32x32-browser-manifest.png",
      "48": "static/media/bn-icon-black-48x48-browser-manifest.png",
      "64": "static/media/bn-icon-black-64x64-browser-manifest.png",
      "128": "static/media/bn-icon-black-128x128-browser-manifest.png"
    }
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "optional_permissions": [
    "cookies",
    "topSites",
    "https://api.brisknote.com/*",
    "https://db.brisknote.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://api.brisknote.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "index.html"
      ],
      "matches": [
        "https://api.brisknote.com/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{90044f1c-2c1c-4bf5-ab79-334b624d1fbe}"
    }
  }
}