Examine source code of Copy Sequence

{
  "manifest_version": 2,
  "name": "Copy Sequence",
  "version": "1",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "32": "image.png"
  },
  "permissions": [
    "contextMenus",
    "clipboardWrite"
  ]
}