Examine source code of Harvest Extension

{
  "manifest_version": 2,
  "name": "Harvest",
  "version": "1.0",
  "description": "Havest is a browser extension that constantly works in the background analysing the products you are shopping for. Harvest will suggest alternative sustainable products for anything you are trying to buy",
  "icons": {
    "48": "/assets/harvest-main-logo.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "src/js/sample_extension.js"
      ]
    }
  ],
  "permissions": [
    "http://localhost/*",
    "https://harvest-ext.herokuapp.com/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Harvest"
  },
  "web_accessible_resources": [
    "/src/js/*"
  ]
}