Examine source code of SSO No Phishing

{
  "manifest_version": 2,
  "name": "SSO No Phishing",
  "version": "1.1.8",
  "description": "Detects if a site is trying to phish your SSO credentials and automatically blocks it (defaults to Mozilla IAM settings)",
  "icons": {
    "48": "icon.png",
    "96": "icon@2x.png"
  },
  "applications": {
    "gecko": {
      "id": "@sso-no-phishing",
      "strict_min_version": "66.0"
    }
  },
  "options_ui": {
    "page": "options.html"
  },
  "homepage_url": "https://github.com/mozilla-iam/sso-no-phishing",
  "permissions": [
    "<all_urls>",
    "browsingData",
    "storage",
    "webRequestBlocking",
    "webRequest",
    "activeTab",
    "tabs",
    "theme"
  ],
  "background": {
    "scripts": [
      "sha256.js",
      "background.js"
    ]
  },
  "web_accessible_resources": [
    "warning.html"
  ]
}