Examine source code of KillTheX

{
  "manifest_version": 2,
  "name": "KillTheX",
  "version": "1.1",
  "description": "Removes all Xs from Twitter",
  "permissions": [
    "webNavigation"
  ],
  "icons": {},
  "content_scripts": [
    {
      "matches": [
        "*://*.twitter.com/*",
        "*://*.x.com/*"
      ],
      "js": [
        "remove.js"
      ],
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    "images/icon.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f669ac65-6e9d-48cc-bd16-8af49678deff}"
    }
  }
}