Examine source code of BMI Calculator v3

{
  "manifest_version": 2,
  "name": "BMI Calculator",
  "version": "1.0",
  "description": "A simple tool to calculate and understand your Body Mass Index (BMI).",
  "icons": {
    "48": "icons/bmi-icon-48.png"
  },
  "permissions": [],
  "browser_action": {
    "default_icon": "icons/bmi-icon-48.png",
    "default_popup": "popup.html",
    "default_title": "BMI Calculator"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{37e5afdd-3897-429d-aec4-eebd103e2524}"
    }
  }
}