Examine source code of PracticeSync for Shepherd

{
  "name": "PracticeSync Payments for Shepherd",
  "description": "A payment integration extension for sending payments to card reader terminals.",
  "version": "1.2.8",
  "manifest_version": 2,
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "applications": {
    "gecko": {
      "id": "shepherd@4act.com",
      "strict_min_version": "58.0"
    }
  },
  "permissions": [
    "storage",
    "activeTab",
    "*://localhost/*",
    "*://vsmart.vsurv.com/*",
    "https://*.shepherd.vet/*"
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "sw.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.shepherd.vet/*"
      ],
      "all_frames": true,
      "run_at": "document_start",
      "js": [
        "inject-shadow-open.js"
      ]
    },
    {
      "matches": [
        "https://*.shepherd.vet/*"
      ],
      "all_frames": true,
      "run_at": "document_end",
      "js": [
        "jquery-3.6.0.min.js",
        "jquery-ui.min.js",
        "shared/sharedPaymentFunctions.js",
        "lib/querySelectorShadowDom.umd.js",
        "pims/shepherd/shepherd.js"
      ],
      "css": [
        "jquery-ui.min.css",
        "extension.css"
      ]
    }
  ],
  "web_accessible_resources": [
    "shadow-open.js"
  ]
}