Examine source code of Copy Advanced

{
  "manifest_version": 2,
  "name": "Copy Advanced",
  "description": "Have more control over what you can copy from webpages. \n\nThis extension allows you to copy the following: \n\n✓ Link text\n✓ Link location\n✓ The inner HTML of any element\n✓ The value of any text field or text area (even if it is disabled)\n✓ The selected text without any formatting\n✓ The selected text without the leading and proceeding whitespace (trimmed)\n\nPlease visit our homepage if you have any feedback or suggestions.",
  "version": "1.0",
  "homepage_url": "http://suttonapps.nz",
  "icons": {
    "48": "logo48.png",
    "96": "logo96.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab",
    "clipboardWrite",
    "menus"
  ]
}