Examine source code of PX => REM; REM => PX

{
  "name": "PX => REM; REM => PX",
  "version": "1.0.0",
  "description": "PX / REM bidirectional converter",
  "manifest_version": 2,
  "homepage_url": "https://qanapa.com",
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "converters.js"
      ]
    }
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "128": "icon128.png"
    },
    "default_title": "PX => REM; REM => PX",
    "default_popup": "/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{346056b5-2dbf-486e-a0cf-8114b7edcfee}"
    }
  }
}