Examine source code of Dax In Space

{
  "description": "Shows today's Astronomy Picture of the Day (APOD) from NASA as the background to the DuckDuckGo homepage.",
  "manifest_version": 2,
  "name": "Dax In Space",
  "version": "1.4resigned1",
  "icons": {
    "32": "icons/dax-in-space_32.png",
    "48": "icons/dax-in-space_48.png",
    "64": "icons/dax-in-space_64.png",
    "128": "icons/dax-in-space_128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.duckduckgo.com/*"
      ],
      "js": [
        "dax-in-space.js"
      ],
      "css": [
        "dax-in-space.css"
      ]
    }
  ],
  "permissions": [
    "*://api.nasa.gov/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{870802ac-29fe-41e5-b4c4-4f9961a57587}"
    }
  }
}