Examine source code of Remove X-Frame-Options

{
  "manifest_version": 2,
  "name": "Remove X-Frame-Options",
  "version": "1.0",
  "description": "Removes the X-Frame-Options header from responses",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2b7270d3-ff4c-42f1-a880-c3d736d95d1a}"
    }
  }
}