Examine source code of Why Salesforce

{
  "manifest_version": 3,
  "name": "Why Salesforce",
  "version": "1.8",
  "permissions": [
    "storage"
  ],
  "description": "Stuff that Salesforce should have added already... Adding flow and user tabs into setup.",
  "homepage_url": "https://github.com/walters954/why-salesforce/tree/firefox",
  "host_permissions": [
    "*://*.lightning.force.com/lightning/setup/*",
    "*://*.salesforce-setup.com/lightning/setup/*"
  ],
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "*://*.lightning.force.com/lightning/setup/*",
        "*://*.salesforce-setup.com/lightning/setup/*"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "16": "images/whysf16.png",
    "32": "images/whysf32.png",
    "48": "images/whysf48.png",
    "128": "images/whysf128.png"
  },
  "action": {
    "default_title": "Why Salesforce",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "whysf@plugin"
    }
  }
}