Examine source code of Medium Referer Unlocker

{
  "manifest_version": 2,
  "name": "Medium Referer Unlocker",
  "description": "Modifies the HTTP referer header to bypass Medium’s paywall and allow full access to Medium articles without login or subscription",
  "version": "1.1.0",
  "icons": {
    "512": "icon_on.png"
  },
  "browser_action": {
    "default_icon": "icon_on.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "https://*.medium.com/*",
    "webRequest",
    "webRequestBlocking",
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "bgp.js"
    ],
    "persistent": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{eb5fa1ce-a024-4cfe-b88b-43d42ed156b4}"
    }
  }
}