Examine source code of LightRead

{
  "manifest_version": 2,
  "name": "LightRead",
  "version": "1.0",
  "description": "Removes header with borrowing controls from the page while reading a book from Archive.org.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/border-48.png",
    "default_title": "LightRead",
    "default_popup": "popup/main.html"
  }
}