Examine source code of Harbor Freight Coupons

{
  "name": "Harbor Freight Coupons",
  "short_name": "harbor freight coupon database extension",
  "version": "2.0.1",
  "manifest_version": 2,
  "description": "Automatically find and display harbor freight coupons on their website from hfqpdb.com",
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_action": {
    "default_icon": "icons/icon32.png"
  },
  "permissions": [
    "https://www.hfqpdb.com/price_check/*",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.harborfreight.com/*",
        "https://shop.harborfreight.com/*"
      ],
      "js": [
        "helper.js",
        "coupons.js"
      ],
      "run_at": "document_idle"
    }
  ]
}