Examine source code of Matrix Calculator

{
  "name": "Matrix Calculator",
  "version": "1.0.2",
  "description": "calculate 3x3 matrix",
  "manifest_version": 3,
  "author": "gp-5",
  "action": {
    "default_popup": "index.html",
    "default_title": "Matrix calculator"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{393d7819-0ce7-4021-865c-a5e3f5a01ae0}"
    }
  }
}