Examine source code of Day Night Dynamic Theme

{
  "manifest_version": 2,
  "name": "Day Night Dynamic Theme",
  "version": "1.3",
  "description": "A theme that changes throughout the day and night.",
  "homepage_url": "https://github.com/Aquafortis/day-night-dynamic-theme",
  "icons": {
    "48": "icons/icon.png",
    "96": "icons/icon@2x.png"
  },
  "permissions": [
    "alarms",
    "theme"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "day-night-theme@aquafortis",
      "strict_min_version": "55.0a2"
    }
  }
}