Examine source code of DG Clip All Button

{
  "name": "DG Clip All Button",
  "author": "Jon Spencer",
  "version": "1.0",
  "description": "Add a Button to the Dollar General Website to Clip all the visible Coupons at once.",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": [
        "https://dg.coupons.com/coupons/",
        "https://dg.coupons.com/coupons/*"
      ],
      "run_at": "document_idle",
      "all_frames": true,
      "js": [
        "ClipAll.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ]
}