Examine source code of Ponder

{
  "manifest_version": 2,
  "name": "Ponder",
  "description": "Daily journal from your new tab.",
  "version": "1.2.4",
  "omnibox": {
    "keyword": "write"
  },
  "options_ui": {
    "page": "popup.html",
    "chrome_style": true
  },
  "browser_action": {
    "default_icon": "icon.png"
  },
  "commands": {
    "freewrite": {
      "suggested_key": {
        "default": "Ctrl+Shift+E",
        "mac": "Command+Shift+E"
      },
      "description": "Open Free Write"
    }
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "background": {
    "scripts": [
      "js/vendor.js",
      "js/background.js"
    ]
  },
  "permissions": [
    "storage",
    "unlimitedStorage",
    "cookies"
  ],
  "optional_permissions": [
    "tabs",
    "*://*.kevinafang.com/*",
    "*://*.getponder.app/*"
  ],
  "applications": {
    "gecko": {
      "id": "extension@getponder.app"
    }
  },
  "icons": {
    "16": "favicon-16x16.png",
    "128": "icon@128.png"
  }
}