X (Twitter) Post Text Editor - Bold, Italic, Underline

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "X (Twitter) Post Text Editor - Bold, Italic, Underline",
  "description": "Enables bold, italic, and underlined text in Twitter posts!",
  "manifest_version": 3,
  "version": "1.0.4",
  "action": {},
  "permissions": [
    "tabs",
    "scripting",
    "activeTab"
  ],
  "host_permissions": [
    "*://*.twitter.com/*",
    "*://*.x.com/*"
  ],
  "icons": {
    "16": "assets/icon-16.png",
    "48": "assets/icon-48.png",
    "128": "assets/icon-128.png"
  },
  "background": {
    "service_worker": "background.js"
  },
  "content_scripts": [
    {
      "js": [
        "jquery.js",
        "content.js"
      ],
      "css": [
        "style.css"
      ],
      "matches": [
        "*://*.twitter.com/*",
        "*://*.x.com/*"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "assets/*"
      ],
      "matches": [
        "*://*.twitter.com/*",
        "*://*.x.com/*"
      ]
    }
  ]
}