Examine source code of readtab

{
  "name": "atext",
  "description": "textonly features to extract mainly text from web pages. The purpose is to declutter rich content web pages. Click on the icon for its action for text page rendering.",
  "version": "2.0",
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js?0"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "jquery-3.4.1.min.js",
        "content.js?0"
      ]
    }
  ],
  "web_accessible_resources": [
    "gpl-1.0.txt?0",
    "popup.html?0",
    "page.html?0"
  ],
  "browser_action": {
    "default_icon": "default-64.png",
    "default_title": "Textonly"
  },
  "incognito": "spanning",
  "options_ui": {
    "page": "./options.html?0"
  },
  "manifest_version": 2
}