Examine source code of MoonPhase

{
  "manifest_version": 2,
  "name": "FullMoon",
  "version": "0.1.0",
  "description": "Check the current moon phase, next full moon date",
  "applications": {
    "gecko": {
      "id": "support@aogobo.com",
      "strict_min_version": "102.0"
    }
  },
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "48": "icon-48.png",
    "128": "icon-128.png",
    "256": "icon-256.png",
    "512": "icon-512.png"
  },
  "browser_action": {
    "default_title": "FullMoon",
    "default_popup": "moon-phase.html",
    "default_icon": {
      "16": "icon-16.png",
      "32": "icon-32.png",
      "48": "icon-48.png"
    }
  },
  "content_security_policy": "script-src 'self' 'sha256-00rWaLO/a+dhFz167aiN7eIDWYJslfCrHTLkGYFKyRM=' 'wasm-unsafe-eval'; object-src 'self';",
  "permissions": [
    "https://cal.next-full-moon.com/*"
  ]
}