Examine source code of Civilifier

{
  "manifest_version": 2,
  "name": "Civilifier",
  "version": "1.4",
  "description": "Make discussions civil again",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png",
    "256": "icons/icon-256.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{887188e0-7f81-49e5-bf10-667e0b4dd290}",
      "strict_min_version": "112.0"
    }
  },
  "permissions": [
    "storage",
    "https://twitter.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false,
    "type": "module"
  },
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "options_ui": {
    "page": "popup.html",
    "open_in_tab": true
  },
  "browser_action": {
    "default_popup": "popup.html"
  }
}