Examine source code of Profit margin calculator

{
  "name": "Profit margin",
  "description": "Profit calculator extension",
  "version": "1.0.0",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "src/popup.html"
  },
  "background": {
    "scripts": [
      "src/background.js"
    ]
  },
  "icons": {
    "16": "icon/icon.png",
    "32": "icon/icon.png",
    "48": "icon/icon.png",
    "128": "icon/icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a6eb97b0-3342-410b-aa3e-be1de5936745}"
    }
  }
}