Examine source code of XCancel

{
  "name": "XCancel",
  "description": "Use XCancel instead of Twitter.",
  "version": "4.1",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko_android": {},
    "gecko": {
      "id": "{7b74340a-30bf-4a45-aefa-8a0de3096062}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "256": "xcancel.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*.twitter.com/*",
    "*://*.x.com/*"
  ]
}