Examine source code of BetterHighlighter

{
  "manifest_version": 2,
  "name": "BetterHighlighter",
  "version": "1.1.1",
  "description": "An extention makes your selection highlighting better",
  "author": "Abu Tuqa Al-Qassasi",
  "applications": {
    "gecko": {
      "id": "qassasi@proton.me",
      "strict_min_version": "78.0"
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "<all_urls>"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "BetterHighlighting",
    "default_icon": {
      "128": "BetterHighlighter_Icon.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "styles.css"
      ]
    }
  ]
}